The Scientific World Journal: Electronics http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Miniaturized Bandpass Filter Using a Meandered Stepped-Impedance Resonator with a Meandered-Line Stub-Load on a GaAs Substrate Mon, 20 Oct 2014 09:11:44 +0000 http://www.hindawi.com/journals/tswj/2014/809809/ This paper reports a compact bandpass filter with improved skirt selectivity using integrated passive device fabrication technology on a GaAs substrate. The structure of the filter consists of electromagnetically coupled meandered-line symmetric stepped-impedance resonators. The strength of the coupling between the resonators is enhanced by using a meandered-line stub-load inside the resonators to improve the selectivity and miniaturize the size of the filter. In addition, the center frequency of the filter can be flexibly controlled by varying degrees of the capacitive coupling between resonator and stub-load. To verify the proposed concept, a protocol bandpass filter with center frequency of 6.53 GHz was designed, fabricated, and measured, with a return loss and insertion loss of 39.1 dB and 1.63 dB. Z. Chuluunbaatar, C. Wang, and N. Y. Kim Copyright © 2014 Z. Chuluunbaatar et al. All rights reserved. Closed-Form Equation of Data Dependent Jitter in First Order Low Pass System Thu, 16 Oct 2014 07:13:33 +0000 http://www.hindawi.com/journals/tswj/2014/694178/ This paper presents a closed-form equation of data dependent jitter (DDJ) in first order low pass systems. The DDJ relates to the system bandwidth, the bit rate, the input rise/fall time, and the number of maximum consecutive identical bits of the data pattern. To confirm the derived equation, simulations have been done with a first order RC low pass circuit for various system bandwidths, bit rates, input rise/fall times, and data patterns. The simulation results agree well with the calculated DDJ values by the derived equation. Sangjin Byun Copyright © 2014 Sangjin Byun. All rights reserved. A Modular Neural Network Scheme Applied to Fault Diagnosis in Electric Power Systems Wed, 17 Sep 2014 09:06:27 +0000 http://www.hindawi.com/journals/tswj/2014/176463/ This work proposes a new method for fault diagnosis in electric power systems based on neural modules. With this method the diagnosis is performed by assigning a neural module for each type of component comprising the electric power system, whether it is a transmission line, bus or transformer. The neural modules for buses and transformers comprise two diagnostic levels which take into consideration the logic states of switches and relays, both internal and back-up, with the exception of the neural module for transmission lines which also has a third diagnostic level which takes into account the oscillograms of fault voltages and currents as well as the frequency spectrums of these oscillograms, in order to verify if the transmission line had in fact been subjected to a fault. One important advantage of the diagnostic system proposed is that its implementation does not require the use of a network configurator for the system; it does not depend on the size of the power network nor does it require retraining of the neural modules if the power network increases in size, making its application possible to only one component, a specific area, or the whole context of the power system. Agustín Flores, Eduardo Quiles, Emilio García, Francisco Morant, and Antonio Correcher Copyright © 2014 Agustín Flores et al. All rights reserved. Novel Modulation Method for Multidirectional Matrix Converter Sun, 14 Sep 2014 11:33:42 +0000 http://www.hindawi.com/journals/tswj/2014/645734/ This study presents a new modulation method for multidirectional matrix converter (MDMC), based on the direct duty ratio pulse width modulation (DDPWM). In this study, a new structure of MDMC has been proposed to control the power flow direction through the stand-alone battery based system and hybrid vehicle. The modulation method acts based on the average voltage over one switching period concept. Therefore, in order to determine the duty ratio for each switch, the instantaneous input voltages are captured and compared with triangular waveform continuously. By selecting the proper switching pattern and changing the slope of the carriers, the sinusoidal input current can be synthesized with high power factor and desired output voltage. The proposed system increases the discharging time of the battery by injecting the power to the system from the generator and battery at the same time. Thus, it makes the battery life longer and saves more energy. This paper also derived necessary equation for proposed modulation method as well as detail of analysis and modulation algorithm. The theoretical and modulation concepts presented have been verified in MATLAB simulation. Saman Toosi, Norhisam Misron, Tsuyoshi Hanamoto, Ishak Bin Aris, Mohd Amran Mohd Radzi, and Hiroaki Yamada Copyright © 2014 Saman Toosi et al. All rights reserved. Distributed Cooperative Regulation for Multiagent Systems and Its Applications to Power Systems: A Survey Wed, 27 Aug 2014 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2014/139028/ Cooperative regulation of multiagent systems has become an active research area in the past decade. This paper reviews some recent progress in distributed coordination control for leader-following multiagent systems and its applications in power system and mainly focuses on the cooperative tracking control in terms of consensus tracking control and containment tracking control. Next, methods on how to rank the network nodes are summarized for undirected/directed network, based on which one can determine which follower should be connected to leaders such that partial followers can perceive leaders’ information. Furthermore, we present a survey of the most relevant scientific studies investigating the regulation and optimization problems in power systems based on distributed strategies. Finally, some potential applications in the frequency tracking regulation of smart grids are discussed at the end of the paper. Jianqiang Hu, Yaping Li, Taiyou Yong, Jinde Cao, Jie Yu, and Wenbo Mao Copyright © 2014 Jianqiang Hu et al. All rights reserved. The Effects of the Reverse Current Caused by the Series Compensation on the Current Differential Protection Tue, 26 Aug 2014 11:13:28 +0000 http://www.hindawi.com/journals/tswj/2014/473913/ The series capacitor compensation is one of the key technologies in the EHV and UHV long distance power transmission lines. This paper analyzes the operation characteristics of the main protection combined with the engineering practice when the transmission line overcompensation due to the series compensation system is modified and analyzes the influence of the transition resistance and the system operation mode on the current differential protection. According to the simulation results, it presents countermeasure on improving the sensitivity of differential current protection. Cui Tang, Xianggen Yin, Xuanwei Qi, Zhe Zhang, and Minghao Wen Copyright © 2014 Cui Tang et al. All rights reserved. Consensus Tracking for Multiagent Systems with Nonlinear Dynamics Thu, 14 Aug 2014 11:33:54 +0000 http://www.hindawi.com/journals/tswj/2014/130643/ This paper concerns the problem of consensus tracking for multiagent systems with a dynamical leader. In particular, it proposes the corresponding explicit control laws for multiple first-order nonlinear systems, second-order nonlinear systems, and quite general nonlinear systems based on the leader-follower and the tree shaped network topologies. Several numerical simulations are given to verify the theoretical results. Runsha Dong Copyright © 2014 Runsha Dong. All rights reserved. Ultra-Low-Voltage CMOS-Based Current Bleeding Mixer with High LO-RF Isolation Thu, 14 Aug 2014 11:08:44 +0000 http://www.hindawi.com/journals/tswj/2014/163414/ This journal presents an ultra-low-voltage current bleeding mixer with high LO-RF port-to-port isolation, implemented on 0.13 μm standard CMOS technology for ZigBee application. The architecture compliments a modified current bleeding topology, consisting of NMOS-based current bleeding transistor, PMOS-based switching stage, and integrated inductors achieving low-voltage operation and high LO-RF isolation. The mixer exhibits a conversion gain of 7.5 dB at the radio frequency (RF) of 2.4 GHz, an input third-order intercept point (IIP3) of 1 dBm, and a LO-RF isolation measured to 60 dB. The DC power consumption is 572 µW at supply voltage of 0.45 V, while consuming a chip area of 0.97 × 0.88 mm2. Gim Heng Tan, Roslina Mohd Sidek, Harikrishnan Ramiah, Wei Keat Chong, and De Xing Lioe Copyright © 2014 Gim Heng Tan et al. All rights reserved. A Novel Sample Based Quadrature Phase Shift Keying Demodulator Thu, 14 Aug 2014 08:56:27 +0000 http://www.hindawi.com/journals/tswj/2014/107831/ This paper presents a new practical QPSK receiver that uses digitized samples of incoming QPSK analog signal to determine the phase of the QPSK symbol. The proposed technique is more robust to phase noise and consumes up to 89.6% less power for signal detection in demodulation operation. On the contrary, the conventional QPSK demodulation process where it uses coherent detection technique requires the exact incoming signal frequency; thus, any variation in the frequency of the local oscillator or incoming signal will cause phase noise. A software simulation of the proposed design was successfully carried out using MATLAB Simulink software platform. In the conventional system, at least 10 dB signal to noise ratio (SNR) is required to achieve the bit error rate (BER) of 10−6, whereas, in the proposed technique, the same BER value can be achieved with only 5 dB SNR. Since some of the power consuming elements such as voltage control oscillator (VCO), mixer, and low pass filter (LPF) are no longer needed, the proposed QPSK demodulator will consume almost 68.8% to 99.6% less operational power compared to conventional QPSK demodulator. Asraf Mohamed Moubark and Sawal Hamid Md Ali Copyright © 2014 Asraf Mohamed Moubark and Sawal Hamid Md Ali. All rights reserved. A Novel Memristive Multilayer Feedforward Small-World Neural Network with Its Applications in PID Control Thu, 14 Aug 2014 08:54:01 +0000 http://www.hindawi.com/journals/tswj/2014/394828/ In this paper, we present an implementation scheme of memristor-based multilayer feedforward small-world neural network (MFSNN) inspirited by the lack of the hardware realization of the MFSNN on account of the need of a large number of electronic neurons and synapses. More specially, a mathematical closed-form charge-governed memristor model is presented with derivation procedures and the corresponding Simulink model is presented, which is an essential block for realizing the memristive synapse and the activation function in electronic neurons. Furthermore, we investigate a more intelligent memristive PID controller by incorporating the proposed MFSNN into intelligent PID control based on the advantages of the memristive MFSNN on computation speed and accuracy. Finally, numerical simulations have demonstrated the effectiveness of the proposed scheme. Zhekang Dong, Shukai Duan, Xiaofang Hu, Lidan Wang, and Hai Li Copyright © 2014 Zhekang Dong et al. All rights reserved. Modified Hyperspheres Algorithm to Trace Homotopy Curves of Nonlinear Circuits Composed by Piecewise Linear Modelled Devices Mon, 11 Aug 2014 08:25:33 +0000 http://www.hindawi.com/journals/tswj/2014/938598/ We present a homotopy continuation method (HCM) for finding multiple operating points of nonlinear circuits composed of devices modelled by using piecewise linear (PWL) representations. We propose an adaptation of the modified spheres path tracking algorithm to trace the homotopy trajectories of PWL circuits. In order to assess the benefits of this proposal, four nonlinear circuits composed of piecewise linear modelled devices are analysed to determine their multiple operating points. The results show that HCM can find multiple solutions within a single homotopy trajectory. Furthermore, we take advantage of the fact that homotopy trajectories are PWL curves meant to replace the multidimensional interpolation and fine tuning stages of the path tracking algorithm with a simple and highly accurate procedure based on the parametric straight line equation. H. Vazquez-Leal, V. M. Jimenez-Fernandez, B. Benhammouda, U. Filobello-Nino, A. Sarmiento-Reyes, A. Ramirez-Pinero, A. Marin-Hernandez, and J. Huerta-Chua Copyright © 2014 H. Vazquez-Leal et al. All rights reserved. Performance Analysis of Autonomous Microgrid Subsequent to Symmetrical and Unsymmetrical Fault Triggered Condition Mon, 04 Aug 2014 05:35:04 +0000 http://www.hindawi.com/journals/tswj/2014/715963/ Hi-tech scenario and the ecological compression are the key point to drive the intervention of the renewable in the distribution system. In the perspective of complex power system planners, the transient performance of the microgrid is the main concern. For that purpose, various fault cases are explored in order to examine the microgrid transient performance when subjected to accidental events. In this work, the microgrid is modelled with two distributed generations (DGs) tied with a converter separately. With this intention, droop control strategy is adopted for the microsources to examine the microgrid performance during the symmetrical and unsymmetrical fault events. The ability of the control strategy adopted in this work and its effectiveness are evaluated through Matlab/Simulink platform. Chitra Natesan, Senthil Kumar Ajithan, Shobana Mani, Priyadharshini Palani, and Prabaakaran Kandhasamy Copyright © 2014 Chitra Natesan et al. All rights reserved. A Novel Prediction Method about Single Components of Analog Circuits Based on Complex Field Modeling Tue, 22 Jul 2014 14:04:31 +0000 http://www.hindawi.com/journals/tswj/2014/530942/ Few researches pay attention to prediction about analog circuits. The few methods lack the correlation with circuit analysis during extracting and calculating features so that FI (fault indicator) calculation often lack rationality, thus affecting prognostic performance. To solve the above problem, this paper proposes a novel prediction method about single components of analog circuits based on complex field modeling. Aiming at the feature that faults of single components hold the largest number in analog circuits, the method starts with circuit structure, analyzes transfer function of circuits, and implements complex field modeling. Then, by an established parameter scanning model related to complex field, it analyzes the relationship between parameter variation and degeneration of single components in the model in order to obtain a more reasonable FI feature set via calculation. According to the obtained FI feature set, it establishes a novel model about degeneration trend of analog circuits’ single components. At last, it uses particle filter (PF) to update parameters for the model and predicts remaining useful performance (RUP) of analog circuits’ single components. Since calculation about the FI feature set is more reasonable, accuracy of prediction is improved to some extent. Finally, the foregoing conclusions are verified by experiments. Jingyu Zhou, Shulin Tian, and Chenglin Yang Copyright © 2014 Jingyu Zhou et al. All rights reserved. Multivariable Time Series Prediction for the Icing Process on Overhead Power Transmission Line Thu, 17 Jul 2014 09:51:59 +0000 http://www.hindawi.com/journals/tswj/2014/256815/ The design of monitoring and predictive alarm systems is necessary for successful overhead power transmission line icing. Given the characteristics of complexity, nonlinearity, and fitfulness in the line icing process, a model based on a multivariable time series is presented here to predict the icing load of a transmission line. In this model, the time effects of micrometeorology parameters for the icing process have been analyzed. The phase-space reconstruction theory and machine learning method were then applied to establish the prediction model, which fully utilized the history of multivariable time series data in local monitoring systems to represent the mapping relationship between icing load and micrometeorology factors. Relevant to the characteristic of fitfulness in line icing, the simulations were carried out during the same icing process or different process to test the model’s prediction precision and robustness. According to the simulation results for the Tao-Luo-Xiong Transmission Line, this model demonstrates a good accuracy of prediction in different process, if the prediction length is less than two hours, and would be helpful for power grid departments when deciding to take action in advance to address potential icing disasters. Peng Li, Na Zhao, Donghua Zhou, Min Cao, Jingjie Li, and Xinling Shi Copyright © 2014 Peng Li et al. All rights reserved. Graph-Based Symbolic Technique and Its Application in the Frequency Response Bound Analysis of Analog Integrated Circuits Thu, 17 Jul 2014 08:00:00 +0000 http://www.hindawi.com/journals/tswj/2014/202371/ A new graph-based symbolic technique (GBST) for deriving exact analytical expressions like the transfer function of an analog integrated circuit (IC), is introduced herein. The derived of a given analog IC is used to compute the frequency response bounds (maximum and minimum) associated to the magnitude and phase of , subject to some ranges of process variational parameters, and by performing nonlinear constrained optimization. Our simulations demonstrate the usefulness of the new GBST for deriving the exact symbolic expression for , and the last section highlights the good agreement between the frequency response bounds computed by our variational analysis approach versus traditional Monte Carlo simulations. As a conclusion, performing variational analysis using our proposed GBST for computing the frequency response bounds of analog ICs, shows a gain in computing time of 100x for a differential circuit topology and 50x for a 3-stage amplifier, compared to traditional Monte Carlo simulations. E. Tlelo-Cuautle, S. Rodriguez-Chavez, and A. A. Palma-Rodriguez Copyright © 2014 E. Tlelo-Cuautle et al. All rights reserved. Method to Eliminate Flux Linkage DC Component in Load Transformer for Static Transfer Switch Thu, 17 Jul 2014 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2014/724529/ Many industrial and commercial sensitive loads are subject to the voltage sags and interruptions. The static transfer switch (STS) based on the thyristors is applied to improve the power quality and reliability. However, the transfer will result in severe inrush current in the load transformer, because of the DC component in the magnetic flux generated in the transfer process. The inrush current which is always 2~30 p.u. can cause the disoperation of relay protective devices and bring potential damage to the transformer. The way to eliminate the DC component is to transfer the related phases when the residual flux linkage of the load transformer and the prospective flux linkage of the alternate source are equal. This paper analyzes how the flux linkage of each winding in the load transformer changes in the transfer process. Based on the residual flux linkage when the preferred source is completely disconnected, the method to calculate the proper time point to close each phase of the alternate source is developed. Simulation and laboratory experiments results are presented to show the effectiveness of the transfer method. Yu He, Chengxiong Mao, Jiming Lu, Dan Wang, and Bing Tian Copyright © 2014 Yu He et al. All rights reserved. A Single-Phase Embedded Z-Source DC-AC Inverter Wed, 16 Jul 2014 10:00:17 +0000 http://www.hindawi.com/journals/tswj/2014/539297/ In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively. Se-Jin Kim and Young-Cheol Lim Copyright © 2014 Se-Jin Kim and Young-Cheol Lim. All rights reserved. Simple BiCMOS CCCTA Design and Resistorless Analog Function Realization Wed, 16 Jul 2014 07:18:06 +0000 http://www.hindawi.com/journals/tswj/2014/423979/ The simple realization of the current-controlled conveyor transconductance amplifier (CCCTA) in BiCMOS technology is introduced. The proposed BiCMOS CCCTA realization is based on the use of differential pair and basic current mirror, which results in simple structure. Its characteristics, that is, parasitic resistance and current transfer , are also tunable electronically by external bias currents. The realized circuit is suitable for fabrication using standard 0.35 μm BiCMOS technology. Some simple and compact resistorless applications employing the proposed CCCTA as active elements are also suggested, which show that their circuit characteristics with electronic controllability are obtained. PSPICE simulation results demonstrating the circuit behaviors and confirming the theoretical analysis are performed. Worapong Tangsrirat Copyright © 2014 Worapong Tangsrirat. All rights reserved. A Memristive Hyperchaotic System without Equilibrium Tue, 15 Jul 2014 13:18:36 +0000 http://www.hindawi.com/journals/tswj/2014/368986/ A new memristive system is presented in this paper. The peculiarity of the model is that it does not display any equilibria and exhibits periodic, chaotic, and also hyperchaotic dynamics in a particular range of the parameters space. The behavior of the proposed system is investigated through numerical simulations, such as phase portraits, Lyapunov exponents, and Poincaré sections, and circuital implementation confirmed the hyperchaotic dynamic. Viet-Thanh Pham, Christos Volos, and Lucia Valentina Gambuzza Copyright © 2014 Viet-Thanh Pham et al. All rights reserved. 50 MHz–10 GHz Low-Power Resistive Feedback Current-Reuse Mixer with Inductive Peaking for Cognitive Radio Receiver Mon, 14 Jul 2014 08:49:55 +0000 http://www.hindawi.com/journals/tswj/2014/683971/ A low-power wideband mixer is designed and implemented in 0.13 µm standard CMOS technology based on resistive feedback current-reuse (RFCR) configuration for the application of cognitive radio receiver. The proposed RFCR architecture incorporates an inductive peaking technique to compensate for gain roll-off at high frequency while enhancing the bandwidth. A complementary current-reuse technique is used between transconductance and IF stages to boost the conversion gain without additional power consumption by reusing the DC bias current of the LO stage. This downconversion double-balanced mixer exhibits a high and flat conversion gain (CG) of 14.9 ± 1.4 dB and a noise figure (NF) better than 12.8 dB. The maximum input 1-dB compression point (P1dB) and maximum input third-order intercept point (IIP3) are −13.6 dBm and −4.5 dBm, respectively, over the desired frequency ranging from 50 MHz to 10 GHz. The proposed circuit operates down to a supply headroom of 1 V with a low-power consumption of 3.5 mW. Nandini Vitee, Harikrishnan Ramiah, Wei-Keat Chong, Gim-Heng Tan, Jeevan Kanesan, and Ahmed Wasif Reza Copyright © 2014 Nandini Vitee et al. All rights reserved. Electronically Tunable Quadrature Oscillator Using Grounded Components with Current and Voltage Outputs Thu, 10 Jul 2014 11:29:29 +0000 http://www.hindawi.com/journals/tswj/2014/572165/ The electronically tunable quadrature oscillator using a single multiple-output current controlled current differencing transconductance amplifier (MO-CCCDTA) and grounded passive components is presented. The proposed configuration uses a single MO-CCCDTA, two grounded capacitors and one grounded resistor. Two high-output impedance quadrature current signals and two quadrature voltage signals with 90° phase difference. The oscillation condition and oscillation frequency of the proposed quadrature oscillator are independently controllable. The use of only grounded passive components makes the proposed circuit ideal for integrated circuit implementation. Hua-Pin Chen Copyright © 2014 Hua-Pin Chen. All rights reserved. Research on Radiation Characteristic of Plasma Antenna through FDTD Method Wed, 09 Jul 2014 14:30:56 +0000 http://www.hindawi.com/journals/tswj/2014/290148/ The radiation characteristic of plasma antenna is investigated by using the finite-difference time-domain (FDTD) approach in this paper. Through using FDTD method, we study the propagation of electromagnetic wave in free space in stretched coordinate. And the iterative equations of Maxwell equation are derived. In order to validate the correctness of this method, we simulate the process of electromagnetic wave propagating in free space. Results show that electromagnetic wave spreads out around the signal source and can be absorbed by the perfectly matched layer (PML). Otherwise, we study the propagation of electromagnetic wave in plasma by using the Boltzmann-Maxwell theory. In order to verify this theory, the whole process of electromagnetic wave propagating in plasma under one-dimension case is simulated. Results show that Boltzmann-Maxwell theory can be used to explain the phenomenon of electromagnetic wave propagating in plasma. Finally, the two-dimensional simulation model of plasma antenna is established under the cylindrical coordinate. And the near-field and far-field radiation pattern of plasma antenna are obtained. The experiments show that the variation of electron density can introduce the change of radiation characteristic. Jianming Zhou, Jingjing Fang, Qiuyuan Lu, and Fan Liu Copyright © 2014 Jianming Zhou et al. All rights reserved. A High-Speed and Low-Offset Dynamic Latch Comparator Wed, 09 Jul 2014 11:52:41 +0000 http://www.hindawi.com/journals/tswj/2014/258068/ Circuit intricacy, speed, low-offset voltage, and resolution are essential factors for high-speed applications like analog-to-digital converters (ADCs). The comparator circuit with preamplifier increases the power dissipation, as it requires higher amount of currents than the latch circuitry. In this research, a novel topology of dynamic latch comparator is illustrated, which is able to provide high speed, low offset, and high resolution. Moreover, the circuit is able to reduce the power dissipation as the topology is based on latch circuitry. The cross-coupled circuit mechanism with the regenerative latch is employed for enhancing the dynamic latch comparator performance. In addition, input-tracking phase is used to reduce the offset voltage. The Monte-Carlo simulation results for the designed comparator in 0.18 μm CMOS process show that the equivalent input-referred offset voltage is 720 μV with 3.44 mV standard deviation. The simulated result shows that the designed comparator has 8-bit resolution and dissipates 158.5 μW of power under 1.8 V supply while operating with a clock frequency of 50 MHz. In addition, the proposed dynamic latch comparator has a layout size of . Labonnah Farzana Rahman, Mamun Bin Ibne Reaz, Chia Chieu Yin, Mohammad Marufuzzaman, and Mohammad Anisur Rahman Copyright © 2014 Labonnah Farzana Rahman et al. All rights reserved. Integrated Navigation Fusion Strategy of INS/UWB for Indoor Carrier Attitude Angle and Position Synchronous Tracking Tue, 08 Jul 2014 09:41:24 +0000 http://www.hindawi.com/journals/tswj/2014/215303/ In some GPS failure conditions, positioning for mobile target is difficult. This paper proposed a new method based on INS/UWB for attitude angle and position synchronous tracking of indoor carrier. Firstly, error model of INS/UWB integrated system is built, including error equation of INS and UWB. And combined filtering model of INS/UWB is researched. Simulation results show that the two subsystems are complementary. Secondly, integrated navigation data fusion strategy of INS/UWB based on Kalman filtering theory is proposed. Simulation results show that FAKF method is better than the conventional Kalman filtering. Finally, an indoor experiment platform is established to verify the integrated navigation theory of INS/UWB, which is geared to the needs of coal mine working environment. Static and dynamic positioning results show that the INS/UWB integrated navigation system is stable and real-time, positioning precision meets the requirements of working condition and is better than any independent subsystem. Qigao Fan, Yaheng Wu, Jing Hui, Lei Wu, Zhenzhong Yu, and Lijuan Zhou Copyright © 2014 Qigao Fan et al. All rights reserved. Observer Design for a Core Circadian Rhythm Network Tue, 08 Jul 2014 08:40:44 +0000 http://www.hindawi.com/journals/tswj/2014/476912/ The paper investigates the observer design for a core circadian rhythm network in Drosophila and Neurospora. Based on the constructed highly nonlinear differential equation model and the recently proposed graphical approach, we design a rather simple observer for the circadian rhythm oscillator, which can well track the state of the original system for various input signals. Numerical simulations show the effectiveness of the designed observer. Potential applications of the related investigations include the real-world control and experimental design of the related biological networks. Yuhuan Zhang Copyright © 2014 Yuhuan Zhang. All rights reserved. Low Power Upconversion Mixer for Medical Remote Sensing Tue, 08 Jul 2014 08:08:58 +0000 http://www.hindawi.com/journals/tswj/2014/923893/ This work presents the design of a low power upconversion mixer adapted in medical remote sensing such as wireless endoscopy application. The proposed upconversion mixer operates in ISM band of 433 MHz. With the carrier power of −5 dBm, the proposed mixer has an output inferred 1 dB compression point of −0.5 dBm with a corresponding output third-order intercept point (OIP3) of 7.1 dBm. The design of the upconversion mixer is realized on CMOS 0.13 μm platform, with a current consumption of 594 μA at supply voltage headroom of 1.2 V. De Xing Lioe, Suhaidi Shafie, Harikrishnan Ramiah, and Gim Heng Tan Copyright © 2014 De Xing Lioe et al. All rights reserved. Study of the Effect of Distance and Misalignment between Magnetically Coupled Coils for Wireless Power Transfer in Intraocular Pressure Measurement Sun, 06 Jul 2014 09:13:44 +0000 http://www.hindawi.com/journals/tswj/2014/692434/ An analysis of the effect of distance and alignment between two magnetically coupled coils for wireless power transfer in intraocular pressure measurement is presented. For measurement purposes, a system was fabricated consisting of an external device, which is a Maxwell-Wien bridge circuit variation, in charge of transferring energy to a biomedical implant and reading data from it. The biomedical implant is an RLC tank circuit, encapsulated by a polyimide coating. Power transfer was done by magnetic induction coupling method, by placing one of the inductors of the Maxwell-Wien bridge circuit and the inductor of the implant in close proximity. The Maxwell-Wien bridge circuit was biased with a 10 MHz sinusoidal signal. The analysis presented in this paper proves that wireless transmission of power for intraocular pressure measurement is feasible with the measurement system proposed. In order to have a proper inductive coupling link, special care must be taken when placing the two coils in proximity to avoid misalignment between them. Adrian E. Rendon-Nava, J. Alejandro Díaz-Méndez, Luis Nino-de-Rivera, Wilfrido Calleja-Arriaga, Felix Gil-Carrasco, and Daniela Díaz-Alonso Copyright © 2014 Adrian E. Rendon-Nava et al. All rights reserved. Synchronization Control for Stochastic Neural Networks with Mixed Time-Varying Delays Wed, 02 Jul 2014 07:19:31 +0000 http://www.hindawi.com/journals/tswj/2014/840185/ Synchronization control of stochastic neural networks with time-varying discrete and continuous delays has been investigated. A novel control scheme is proposed using the Lyapunov functional method and linear matrix inequality (LMI) approach. Sufficient conditions have been derived to ensure the global asymptotical mean-square stability for the error system, and thus the drive system synchronizes with the response system. Also, the control gain matrix can be obtained. With these effective methods, synchronization can be achieved. Simulation results are presented to show the effectiveness of the theoretical results. Qing Zhu, Aiguo Song, Shumin Fei, Yuequan Yang, and Zhiqiang Cao Copyright © 2014 Qing Zhu et al. All rights reserved. Numerical Analysis of Modeling Based on Improved Elman Neural Network Wed, 18 Jun 2014 07:01:16 +0000 http://www.hindawi.com/journals/tswj/2014/271593/ A modeling based on the improved Elman neural network (IENN) is proposed to analyze the nonlinear circuits with the memory effect. The hidden layer neurons are activated by a group of Chebyshev orthogonal basis functions instead of sigmoid functions in this model. The error curves of the sum of squared error (SSE) varying with the number of hidden neurons and the iteration step are studied to determine the number of the hidden layer neurons. Simulation results of the half-bridge class-D power amplifier (CDPA) with two-tone signal and broadband signals as input have shown that the proposed behavioral modeling can reconstruct the system of CDPAs accurately and depict the memory effect of CDPAs well. Compared with Volterra-Laguerre (VL) model, Chebyshev neural network (CNN) model, and basic Elman neural network (BENN) model, the proposed model has better performance. Shao Jie, Wang Li, Zhao WeiSong, Zhong YaQin, and Reza Malekian Copyright © 2014 Shao Jie et al. All rights reserved. 2.4 GHz CMOS Power Amplifier with Mode-Locking Structure to Enhance Gain Tue, 17 Jun 2014 07:31:40 +0000 http://www.hindawi.com/journals/tswj/2014/967181/ We propose a mode-locking method optimized for the cascode structure of an RF CMOS power amplifier. To maximize the advantage of the typical mode-locking method in the cascode structure, the input of the cross-coupled transistor is modified from that of a typical mode-locking structure. To prove the feasibility of the proposed structure, we designed a 2.4 GHz CMOS power amplifier with a 0.18 μm RFCMOS process for polar transmitter applications. The measured power added efficiency is 34.9%, while the saturated output power is 23.32 dBm. The designed chip size is  mm2. Changhyun Lee and Changkun Park Copyright © 2014 Changhyun Lee and Changkun Park. All rights reserved. Microstrip Triband Bandstop Fitler with Sharp Stop Band Skirts and Independently Controllable Second Stop Band Response Thu, 12 Jun 2014 05:42:56 +0000 http://www.hindawi.com/journals/tswj/2014/760838/ This paper presents a compact planar triband bandstop filter (TBBSF) with compact size and high selectivity. The structure of the filter incorporates two folded trisection stepped-impedance resonators (TSSIRs). One of these resonators is designed to operate at the first and third center frequencies and the other resonator is designed to operate at the second center frequency of the proposed filter. To achieve a compact size filter, alternating impedance lines of the resonators are folded widthwise and also one resonator is embedded within another. Theoretical analysis and design procedures are described, including the synthesis equations for each resonator. The main advantage of the proposed method is that the filter provides flexibility to tune the second center frequency and control the corresponding bandwidth without changing the first and third stop band response. Additionally, several reflection zeros (RZs) are introduced in the pass band to improve its flatness. To demonstrate the feasibility of the proposed design method, both the first and second order TBBSFs were designed, simulated, and fabricated, with center frequencies of 1.92 GHz, 3.55 GHz, and 5.5 GHz. Kishor Kumar Adhikari and Nam-Young Kim Copyright © 2014 Kishor Kumar Adhikari and Nam-Young Kim. All rights reserved. Hardware Implementation of 32-Bit High-Speed Direct Digital Frequency Synthesizer Mon, 02 Jun 2014 08:53:17 +0000 http://www.hindawi.com/journals/tswj/2014/131568/ The design and implementation of a high-speed direct digital frequency synthesizer are presented. A modified Brent-Kung parallel adder is combined with pipelining technique to improve the speed of the system. A gated clock technique is proposed to reduce the number of registers in the phase accumulator design. The quarter wave symmetry technique is used to store only one quarter of the sine wave. The ROM lookup table (LUT) is partitioned into three 4-bit sub-ROMs based on angular decomposition technique and trigonometric identity. Exploiting the advantages of sine-cosine symmetrical attributes together with XOR logic gates, one sub-ROM block can be removed from the design. These techniques, compressed the ROM into 368 bits. The ROM compressed ratio is 534.2 : 1, with only two adders, two multipliers, and XOR-gates with high frequency resolution of 0.029 Hz. These techniques make the direct digital frequency synthesizer an attractive candidate for wireless communication applications. Salah Hasan Ibrahim, Sawal Hamid Md. Ali, and Md. Shabiul Islam Copyright © 2014 Salah Hasan Ibrahim et al. All rights reserved. Versatile Tunable Current-Mode Universal Biquadratic Filter Using MO-DVCCs and MOSFET-Based Electronic Resistors Sun, 01 Jun 2014 08:11:03 +0000 http://www.hindawi.com/journals/tswj/2014/515348/ This paper presents a versatile tunable current-mode universal biquadratic filter with four-input and three-output employing only two multioutput differential voltage current conveyors (MO-DVCCs), two grounded capacitors, and a well-known method for replacement of three grounded resistors by MOSFET-based electronic resistors. The proposed configuration exhibits high-output impedance which is important for easy cascading in the current-mode operations. The proposed circuit can be used as either a two-input three-output circuit or a three-input single-output circuit. In the operation of two-input three-output circuit, the bandpass, highpass, and bandreject filtering responses can be realized simultaneously while the allpass filtering response can be easily obtained by connecting appropriated output current directly without using additional stages. In the operation of three-input single-output circuit, all five generic filtering functions can be easily realized by selecting different three-input current signals. The filter permits orthogonal controllability of the quality factor and resonance angular frequency, and no inverting-type input current signals are imposed. All the passive and active sensitivities are low. Postlayout simulations were carried out to verify the functionality of the design. Hua-Pin Chen Copyright © 2014 Hua-Pin Chen. All rights reserved. Miniaturized Dual Band Multislotted Patch Antenna on Polytetrafluoroethylene Glass Microfiber Reinforced for C/X Band Applications Sun, 01 Jun 2014 05:51:18 +0000 http://www.hindawi.com/journals/tswj/2014/673846/ This paper introduces a new configuration of compact, triangular- and diamond-slotted, microstrip-fed, low-profile antenna for C/X band applications on polytetrafluoroethylene glass microfiber reinforced material substrate. The antenna is composed of a rectangular-shaped patch containing eight triangles and two diamond-shaped slots and an elliptical-slotted ground plane. The rectangular-shaped patch is obtained by cutting two diamond slots in the middle of the rectangular patch, six triangular slots on the left and right side of the patch, and two triangular slots on the up and down side of the patch. The slotted radiating patch, the elliptical-slotted ground plane, and the microstrip feed enable the matching bandwidth to be widened. A prototype of the optimized antenna was fabricated on polytetrafluoroethylene glass microfiber reinforced material substrate using LPKF prototyping machine and investigated to validate the proposed design. The simulated results are compared with the measured data, and good agreement is achieved. The proposed antenna offers fractional bandwidths of 13.69% (7.78–8.91 GHz) and 10.35% (9.16–10.19 GHz) where S11 < −10 dB at center frequencies of 8.25 GHz and 9.95 GHz, respectively, and relatively stable gain, good radiation efficiency, and omnidirectional radiation patterns in the matching band. M. T. Islam and M. Samsuzzaman Copyright © 2014 M. T. Islam and M. Samsuzzaman. All rights reserved. Circularly Polarized S Band Dual Frequency Square Patch Antenna Using Glass Microfiber Reinforced PTFE Composite Thu, 22 May 2014 06:41:06 +0000 http://www.hindawi.com/journals/tswj/2014/345190/ Circularly polarized (CP) dual frequency cross-shaped slotted patch antenna on 1.575 mm thick glass microfiber reinforced polytetrafluoroethylene (PTFE) composite material substrate is designed and fabricated for satellite applications. Asymmetric cross-shaped slots are embedded in the middle of the square patch for CP radiation and four hexagonal slots are etched on the four sides of the square patch for desired dual frequency. Different substrate materials have been analysed to achieve the desired operating band. The experimental results show that the impedance bandwidth is approximately 30 MHz (2.16 GHz to 2.19 GHz) for lower band and 40 MHz (3.29 GHz to 3.33 GHz) for higher band with an average peak gain of 6.59 dBiC and 5.52 dBiC, respectively. Several optimizations are performed to obtain the values of the antenna physical parameters. Moreover, the proposed antenna possesses compactness, light weight, simplicity, low cost, and circularly polarized. It is an attractive candidate for dual band satellite antennas where lower band can be used for uplink and upper band can be used for downlink. M. Samsuzzaman, M. T. Islam, Haslina Arshad, J. S. Mandeep, and N. Misran Copyright © 2014 M. Samsuzzaman et al. All rights reserved. Voltage-Mode Multifunction Biquadratic Filter with One Input and Six Outputs Using Two ICCIIs Thu, 08 May 2014 12:32:31 +0000 http://www.hindawi.com/journals/tswj/2014/432570/ A novel voltage-mode multifunction biquadratic filter with one input and six outputs is presented. The proposed circuit can realize inverting and noninverting low-pass, bandpass, and high-pass filters, simultaneously, by using two inverting second-generation current conveyors (ICCIIs), two grounded capacitors, and four resistors. Moreover, the proposed circuit offers the following attractive advantages: no requirements for component matching conditions, the use of only grounded capacitors, and low active and passive sensitivities. HSPICE and MATLAB simulations results are provided to demonstrate the theoretical analysis. Hua-Pin Chen Copyright © 2014 Hua-Pin Chen. All rights reserved. Gain Enhancement of a Multiband Resonator Using Defected Ground Surface on Epoxy Woven Glass Material Sun, 27 Apr 2014 09:45:32 +0000 http://www.hindawi.com/journals/tswj/2014/159468/ A multiband microstrip resonator is proposed in this study which is realized through a rectangular radiator with embedded symmetrical rectangular slots in it and a defected ground surface. The study is presented with detailed parametric analyses to understand the effect of various design parameters. The design and analyses are performed using the FIT based full-wave electromagnetic simulator CST microwave studio suite. With selected parameter values, the resonator showed a peak gain of 5.85 dBi at 5.2 GHz, 6.2 dBi at 8.3 GHz, 3.9 dBi at 9.5 GHz, 5.9 dBi at 12.2 GHz, and 4.7 dBi at 14.6 GHz. Meanwhile, the main lobe magnitude and the 3 dB angular beam width are 6.2 dBi and 86°, 5.9 dBi and 53.7°, 8.5 dBi and 43.9°, 8.6 dBi and 42.1°, and 4.7 dBi and 30.1°, respectively, at the resonant frequencies. The overall resonator has a compact dimension of 0.52  × 0.52  × 0.027 at the lower resonant frequency. For practical validation, a lab prototype was built on a 1.6 mm thick epoxide woven glass fabric dielectric material which is measured using a vector network analyzer and within an anechoic chamber. The comparison between the simulated and measured results showed a very good understanding, which implies the practical suitability of the proposed multiband resonator design. Md. Shahidul Alam, Mohammad Tariqul Islam, and Haslina Arshad Copyright © 2014 Md. Shahidul Alam et al. All rights reserved. A ROM-Less Direct Digital Frequency Synthesizer Based on Hybrid Polynomial Approximation Wed, 23 Apr 2014 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2014/812576/ In this paper, a novel design approach for a phase to sinusoid amplitude converter (PSAC) has been investigated. Two segments have been used to approximate the first sine quadrant. A first linear segment is used to fit the region near the zero point, while a second fourth-order parabolic segment is used to approximate the rest of the sine curve. The phase sample, where the polynomial changed, was chosen in such a way as to achieve the maximum spurious free dynamic range (SFDR). The invented direct digital frequency synthesizer (DDFS) has been encoded in VHDL and post simulation was carried out. The synthesized architecture exhibits a promising result of 90 dBc SFDR. The targeted structure is expected to show advantages for perceptible reduction of hardware resources and power consumption as well as high clock speeds. Qahtan Khalaf Omran, Mohammad Tariqul Islam, Norbahiah Misran, and Mohammad Rashed Iqbal Faruque Copyright © 2014 Qahtan Khalaf Omran et al. All rights reserved. Novel Hexagonal Dual-Mode Substrate Integrated Waveguide Filter with Source-Load Coupling Tue, 22 Apr 2014 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2014/915740/ Hexagonal dual-mode cavity and its application to substrate integrated waveguide (SIW) filter are presented. The hexagonal SIW resonator which can combine flexibility of rectangular cavity and performance of circular cavity is convenient for dual-mode bandpass filters design. By introducing coupling between source and load, the filter not only has good selectivity due to two controllable transmission zeros, but also has a small size by the virtue of its single-cavity structure. A demonstration filter with a center frequency of 10 GHz and a 3 dB fractional bandwidth of 4% is designed and fabricated to validate the proposed structure. Measured results are in good agreement with simulated ones. Ziqiang Xu, Gen Zhang, Hong Xia, and Meijuan Xu Copyright © 2014 Ziqiang Xu et al. All rights reserved. Experimental Realization of a Multiscroll Chaotic Oscillator with Optimal Maximum Lyapunov Exponent Wed, 16 Apr 2014 10:28:03 +0000 http://www.hindawi.com/journals/tswj/2014/303614/ Nowadays, different kinds of experimental realizations of chaotic oscillators have been already presented in the literature. However, those realizations do not consider the value of the maximum Lyapunov exponent, which gives a quantitative measure of the grade of unpredictability of chaotic systems. That way, this paper shows the experimental realization of an optimized multiscroll chaotic oscillator based on saturated function series. First, from the mathematical description having four coefficients (a, b, c, d1), an optimization evolutionary algorithm varies them to maximize the value of the positive Lyapunov exponent. Second, a realization of those optimized coefficients using operational amplifiers is given. Herein a, b, c, d1 are implemented with precision potentiometers to tune up to four decimals of the coefficients having the range between 0.0001 and 1.0000. Finally, experimental results of the phase-space portraits for generating from 2 to 10 scrolls are listed to show that their associated value for the optimal maximum Lyapunov exponent increases by increasing the number of scrolls, thus guaranteeing a more complex chaotic behavior. Esteban Tlelo-Cuautle, Ana Dalia Pano-Azucena, Victor Hugo Carbajal-Gomez, and Mauro Sanchez-Sanchez Copyright © 2014 Esteban Tlelo-Cuautle et al. All rights reserved. Analysis of Glass-Reinforced Epoxy Material for Radio Frequency Resonator Sun, 06 Apr 2014 12:54:25 +0000 http://www.hindawi.com/journals/tswj/2014/831435/ A radio frequency (RF) resonator using glass-reinforced epoxy material for C and X band is proposed in this paper. Microstrip line technology for RF over glass-reinforced epoxy material is analyzed. Coupling mechanism over RF material and parasitic coupling performance is explained utilizing even and odd mode impedance with relevant equivalent circuit. Babinet’s principle is deployed to explicate the circular slot ground plane of the proposed resonator. The resonator is designed over four materials from different backgrounds which are glass-reinforced epoxy, polyester, gallium arsenide (GaAs), and rogers RO 4350B. Parametric studies and optimization algorithm are applied over the geometry of the microstrip resonator to achieve dual band response for C and X band. Resonator behaviors for different materials are concluded and compared for the same structure. The final design is fabricated over glass-reinforced epoxy material. The fabricated resonator shows a maximum directivity of 5.65 dBi and 6.62 dBi at 5.84 GHz and 8.16 GHz, respectively. The lowest resonance response is less than −20 dB for C band and −34 dB for X band. The resonator is prototyped using LPKF (S63) drilling machine to study the material behavior. M. R. Zaman, M. T. Islam, N. Misran, and Baharudin Yatim Copyright © 2014 M. R. Zaman et al. All rights reserved. Fast Readout Architectures for Large Arrays of Digital Pixels: Examples and Applications Wed, 19 Mar 2014 13:10:14 +0000 http://www.hindawi.com/journals/tswj/2014/523429/ Modern pixel detectors, particularly those designed and constructed for applications and experiments for high-energy physics, are commonly built implementing general readout architectures, not specifically optimized in terms of speed. High-energy physics experiments use bidimensional matrices of sensitive elements located on a silicon die. Sensors are read out via other integrated circuits bump bonded over the sensor dies. The speed of the readout electronics can significantly increase the overall performance of the system, and so here novel forms of readout architectures are studied and described. These circuits have been investigated in terms of speed and are particularly suited for large monolithic, low-pitch pixel detectors. The idea is to have a small simple structure that may be expanded to fit large matrices without affecting the layout complexity of the chip, while maintaining a reasonably high readout speed. The solutions might be applied to devices for applications not only in physics but also to general-purpose pixel detectors whenever online fast data sparsification is required. The paper presents also simulations on the efficiencies of the systems as proof of concept for the proposed ideas. A. Gabrielli Copyright © 2014 A. Gabrielli. All rights reserved. Single-Event-Upset Sensitivity Analysis on Low-Swing Drivers Wed, 19 Mar 2014 09:02:05 +0000 http://www.hindawi.com/journals/tswj/2014/876435/ Technology scaling relies on reduced nodal capacitances and lower voltages in order to improve performance and power consumption, resulting in significant increase in layout density, thus making these submicron technologies more susceptible to soft errors. Previous analysis indicates a significant improvement in SEU tolerance of the driver when the bias current is injected into the circuit but results in increase of power dissipation. Subsequently, other alternatives are considered. The impact of transistor sizes and temperature on SEU tolerance is tested. Results indicate no significant changes in when the effective transistor length is increased by 10%, but there is an improvement when high temperature and high bias currents are applied. However, this is due to other process parameters that are temperature dependent, which contribute to the sharp increase in . It is found that, with temperature, there is no clear factor that can justify the direct impact of temperature on the SEU tolerance. Thus, in order to improve the SEU tolerance, high bias currents are still considered to be the most effective method in improving the SEU sensitivity. However, good trade-off is required for the low-swing driver in order to meet the reliability target with minimal power overhead. Nor Muzlifah Mahyuddin and Gordon Russell Copyright © 2014 Nor Muzlifah Mahyuddin and Gordon Russell. All rights reserved. An RF Energy Harvester System Using UHF Micropower CMOS Rectifier Based on a Diode Connected CMOS Transistor Mon, 17 Mar 2014 16:48:56 +0000 http://www.hindawi.com/journals/tswj/2014/963709/ This paper presents a new type diode connected MOS transistor to improve CMOS conventional rectifier's performance in RF energy harvester systems for wireless sensor networks in which the circuits are designed in 0.18 μm TSMC CMOS technology. The proposed diode connected MOS transistor uses a new bulk connection which leads to reduction in the threshold voltage and leakage current; therefore, it contributes to increment of the rectifier’s output voltage, output current, and efficiency when it is well important in the conventional CMOS rectifiers. The design technique for the rectifiers is explained and a matching network has been proposed to increase the sensitivity of the proposed rectifier. Five-stage rectifier with a matching network is proposed based on the optimization. The simulation results shows 18.2% improvement in the efficiency of the rectifier circuit and increase in sensitivity of RF energy harvester circuit. All circuits are designed in 0.18 μm TSMC CMOS technology. Mohammad Reza Shokrani, Mojtaba Khoddam, Mohd Nizar B. Hamidon, Noor Ain Kamsani, Fakhrul Zaman Rokhani, and Suhaidi Bin Shafie Copyright © 2014 Mohammad Reza Shokrani et al. All rights reserved. A Real-Time and Closed-Loop Control Algorithm for Cascaded Multilevel Inverter Based on Artificial Neural Network Sun, 16 Mar 2014 11:25:21 +0000 http://www.hindawi.com/journals/tswj/2014/508163/ In order to control the cascaded H-bridges (CHB) converter with staircase modulation strategy in a real-time manner, a real-time and closed-loop control algorithm based on artificial neural network (ANN) for three-phase CHB converter is proposed in this paper. It costs little computation time and memory. It has two steps. In the first step, hierarchical particle swarm optimizer with time-varying acceleration coefficient (HPSO-TVAC) algorithm is employed to minimize the total harmonic distortion (THD) and generate the optimal switching angles offline. In the second step, part of optimal switching angles are used to train an ANN and the well-designed ANN can generate optimal switching angles in a real-time manner. Compared with previous real-time algorithm, the proposed algorithm is suitable for a wider range of modulation index and results in a smaller THD and a lower calculation time. Furthermore, the well-designed ANN is embedded into a closed-loop control algorithm for CHB converter with variable direct voltage (DC) sources. Simulation results demonstrate that the proposed closed-loop control algorithm is able to quickly stabilize load voltage and minimize the line current’s THD (<5%) when subjecting the DC sources disturbance or load disturbance. In real design stage, a switching angle pulse generation scheme is proposed and experiment results verify its correctness. Libing Wang, Chengxiong Mao, Dan Wang, Jiming Lu, Junfeng Zhang, and Xun Chen Copyright © 2014 Libing Wang et al. All rights reserved. A Modified Implementation of Tristate Inverter Based Static Master-Slave Flip-Flop with Improved Power-Delay-Area Product Thu, 27 Feb 2014 16:14:40 +0000 http://www.hindawi.com/journals/tswj/2014/453675/ The paper introduces novel architectures for implementation of fully static master-slave flip-flops for low power, high performance, and high density. Based on the proposed structure, traditional C2MOS latch (tristate inverter/clocked inverter) based flip-flop is implemented with fewer transistors. The modified C2MOS based flip-flop designs mC2MOSff1 and mC2MOSff2 are realized using only sixteen transistors each while the number of clocked transistors is also reduced in case of mC2MOSff1. Postlayout simulations indicate that mC2MOSff1 flip-flop shows 12.4% improvement in PDAP (power-delay-area product) when compared with transmission gate flip-flop (TGFF) at 16X capacitive load which is considered to be the best design alternative among the conventional master-slave flip-flops. To validate the correct behaviour of the proposed design, an eight bit asynchronous counter is designed to layout level. LVS and parasitic extraction were carried out on Calibre, whereas layouts were implemented using IC station (Mentor Graphics). HSPICE simulations were used to characterize the transient response of the flip-flop designs in a 180 nm/1.8 V CMOS technology. Simulations were also performed at 130 nm, 90 nm, and 65 nm to reveal the scalability of both the designs at modern process nodes. Kunwar Singh, Satish Chandra Tiwari, and Maneesha Gupta Copyright © 2014 Kunwar Singh et al. All rights reserved. A Low-Noise Delta-Sigma Phase Modulator for Polar Transmitters Tue, 25 Feb 2014 06:56:01 +0000 http://www.hindawi.com/journals/tswj/2014/521717/ A low-noise phase modulator, using finite-impulse-response (FIR) filtering embedded delta-sigma (ΔΣ) fractional-N phase-locked loop (PLL), is fabricated in 0.18 μm CMOS for GSM/EDGE polar transmitters. A simplified digital compensation filter with inverse-FIR and -PLL features is proposed to trade off the transmitter noise and linearity. Experimental results show that the presented architecture performs RF phase modulation well with 20 mW power dissipation from 1.6 V supply and achieves the root-mean-square (rms) and peak phase errors of 4° and 8.5°, respectively. The measured and simulated phase noises of −104 dBc/Hz and −120 dBc/Hz at 400-kHz offset from 1.8-GHz carrier frequency are observed, respectively. Bo Zhou Copyright © 2014 Bo Zhou. All rights reserved. High Isolation Single-Pole Four-Throw RF MEMS Switch Based on Series-Shunt Configuration Sun, 23 Feb 2014 14:08:58 +0000 http://www.hindawi.com/journals/tswj/2014/605894/ This paper presents a novel design of single-pole four-throw (SP4T) RF-MEMS switch employing both capacitive and ohmic switches. It is designed on high-resistivity silicon substrate and has a compact area of 1.06 mm2. The series or ohmic switches have been designed to provide low insertion loss with good ohmic contact. The pull-in voltage for ohmic switches is calculated to be 7.19 V. Shunt or capacitive switches have been used in each port to improve the isolation for higher frequencies. The proposed SP4T switch provides excellent RF performances with isolation better than 70.64 dB and insertion loss less than 0.72 dB for X-band between the input port and each output port. Tejinder Singh and Navjot Khaira Copyright © 2014 Tejinder Singh and Navjot Khaira. All rights reserved. 100 nm AlSb/InAs HEMT for Ultra-Low-Power Consumption, Low-Noise Applications Sun, 23 Feb 2014 13:17:02 +0000 http://www.hindawi.com/journals/tswj/2014/136340/ We report on high frequency (HF) and noise performances of AlSb/InAs high electron mobility transistor (HEMT) with 100 nm gate length at room temperature in low-power regime. Extrinsic cut-off frequencies of 100/125 GHz together with minimum noise figure  dB and associated gain  dB at 12 GHz have been obtained at drain bias of only 80 mV, corresponding to 4 mW/mm DC power dissipation. This demonstrates the great ability of AlSb/InAs HEMT for high-frequency operation combined with low-noise performances in ultra-low-power regime. Cyrille Gardès, Sonia Bagumako, Ludovic Desplanque, Nicolas Wichmann, Sylvain Bollaert, François Danneville, Xavier Wallart, and Yannick Roelens Copyright © 2014 Cyrille Gardès et al. All rights reserved. Continuous-Time ADC with Implicit Variable Gain Amplifier for CMOS Image Sensor Tue, 18 Feb 2014 11:44:08 +0000 http://www.hindawi.com/journals/tswj/2014/208540/ This paper presents a column-parallel continuous-time sigma delta (CTSD) ADC for mega-pixel resolution CMOS image sensor (CIS). The sigma delta modulator is implemented with a 2nd order resistor/capacitor-based loop filter. The first integrator uses a conventional operational transconductance amplifier (OTA), for the concern of a high power noise rejection. The second integrator is realized with a single-ended inverter-based amplifier, instead of a standard OTA. As a result, the power consumption is reduced, without sacrificing the noise performance. Moreover, the variable gain amplifier in the traditional column-parallel read-out circuit is merged into the front-end of the CTSD modulator. By programming the input resistance, the amplitude range of the input current can be tuned with 8 scales, which is equivalent to a traditional 2-bit preamplification function without consuming extra power and chip area. The test chip prototype is fabricated using 0.18 μm CMOS process and the measurement result shows an ADC power consumption lower than 63.5 μW under 1.4 V power supply and 50 MHz clock frequency. Fang Tang, Amine Bermak, Amira Abbes, and Mohieddine Amor Benammar Copyright © 2014 Fang Tang et al. All rights reserved. SFG Synthesis of General High-Order All-Pass and All-Pole Current Transfer Functions Using CFTAs Tue, 11 Feb 2014 09:02:17 +0000 http://www.hindawi.com/journals/tswj/2014/271926/ An approach of using the signal flow graph (SFG) technique to synthesize general high-order all-pass and all-pole current transfer functions with current follower transconductance amplifiers (CFTAs) and grounded capacitors has been presented. For general nth-order systems, the realized all-pass structure contains at most n + 1 CFTAs and n grounded capacitors, while the all-pole lowpass circuit requires only n CFTAs and n grounded capacitors. The resulting circuits obtained from the synthesis procedure are resistor-less structures and especially suitable for integration. They also exhibit low-input and high-output impedances and also convenient electronic controllability through the -value of the CFTA. Simulation results using real transistor model parameters ALA400 are also included to confirm the theory. Worapong Tangsrirat Copyright © 2014 Worapong Tangsrirat. All rights reserved. Analysis of Paralleling Limited Capacity Voltage Sources by Projective Geometry Method Mon, 10 Feb 2014 12:13:09 +0000 http://www.hindawi.com/journals/tswj/2014/359893/ The droop current-sharing method for voltage sources of a limited capacity is considered. Influence of equalizing resistors and load resistor is investigated on uniform distribution of relative values of currents when the actual loading corresponds to the capacity of a concrete source. Novel concepts for quantitative representation of operating regimes of sources are entered with use of projective geometry method. Alexandr Penin Copyright © 2014 Alexandr Penin. All rights reserved. Multiple Chaos Synchronization System for Power Quality Classification in a Power System Mon, 10 Feb 2014 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2014/902167/ This document proposes multiple chaos synchronization (CS) systems for power quality (PQ) disturbances classification in a power system. Chen-Lee based CS systems use multiple detectors to track the dynamic errors between the normal signal and the disturbance signal, including power harmonics, voltage fluctuation phenomena, and voltage interruptions. Multiple detectors are used to monitor the dynamic errors between the master system and the slave system and are used to construct the feature patterns from time-domain signals. The maximum likelihood method (MLM), as a classifier, performs a comparison of the patterns of the features in the database. The proposed method can adapt itself without the need for adjustment of parameters or iterative computation. For a sample power system, the test results showed accurate discrimination, good robustness, and faster processing time for the detection of PQ disturbances. Cong-Hui Huang and Chia-Hung Lin Copyright © 2014 Cong-Hui Huang and Chia-Hung Lin. All rights reserved. A Dual-Mode Bandpass Filter with Multiple Controllable Transmission-Zeros Using T-Shaped Stub-Loaded Resonators Sun, 09 Feb 2014 13:48:05 +0000 http://www.hindawi.com/journals/tswj/2014/572360/ A dual-mode broadband bandpass filter (BPF) with multiple controllable transmission-zeros using T-shaped stub-loaded resonators (TSSLRs) is presented. Due to the symmetrical plane, the odd-even-mode theory can be adopted to characterize the BPF. The proposed filter consists of a dual-mode TSSLR and two modified feed-lines, which introduce two capacitive and inductive source-load (S-L) couplings. Five controllable transmission zeros (TZs) can be achieved for the high selectivity and the wide stopband because of the tunable amount of coupling capacitance and inductance. The center frequency of the proposed BPF is 5.8 GHz, with a 3 dB fraction bandwidth of 8.9%. The measured insertion and return losses are 1.75 and 28.18 dB, respectively. A compact size and second harmonic frequency suppression can be obtained by the proposed BPF with S-L couplings. Zh. Yao, C. Wang, and N. Y. Kim Copyright © 2014 Zh. Yao et al. All rights reserved. A Novel High-Power Dual-Band Coupled-Line Gysel Power Divider with Impedance-Transforming Functions Sun, 09 Feb 2014 10:21:58 +0000 http://www.hindawi.com/journals/tswj/2014/831073/ A novel coupled-line structure is proposed to design dual-band and high-power Gysel power dividers with inherent impedance-transforming functions. Based on traditional even- and odd-mode technique, the analytical design methods in closed-form formula are obtained and the accurate electrical parameters analysis is presented. Due to the usage of coupled-line sections, more design-parameter freedom and a wider frequency-ratio operation range for this kind of dual-band Gysel powder divider are obtained. Several numerical examples are designed and calculated to demonstrate flexible dual-band applications with different impedance-transforming functions. A practical microstrip power divider operating at 2 GHz and 3.2 GHz is designed, fabricated, and measured. The good agreement between the calculated and measured results verifies our proposed circuit structure and analytical design approach. Weimin Wang, Yongle Wu, and Yuanan Liu Copyright © 2014 Weimin Wang et al. All rights reserved. Comparative Analyses of Phase Noise in 28 nm CMOS LC Oscillator Circuit Topologies: Hartley, Colpitts, and Common-Source Cross-Coupled Differential Pair Thu, 06 Feb 2014 12:48:50 +0000 http://www.hindawi.com/journals/tswj/2014/421321/ This paper reports comparative analyses of phase noise in Hartley, Colpitts, and common-source cross-coupled differential pair LC oscillator topologies in 28 nm CMOS technology. The impulse sensitivity function is used to carry out both qualitative and quantitative analyses of the phase noise exhibited by each circuit component in each circuit topology with oscillation frequency ranging from 1 to 100 GHz. The comparative analyses show the existence of four distinct frequency regions in which the three oscillator topologies rank unevenly in terms of best phase noise performance, due to the combined effects of device noise and circuit node sensitivity. Ilias Chlis, Domenico Pepe, and Domenico Zito Copyright © 2014 Ilias Chlis et al. All rights reserved. Detection of Lungs Status Using Morphological Complexities of Respiratory Sounds Thu, 06 Feb 2014 08:40:58 +0000 http://www.hindawi.com/journals/tswj/2014/182938/ Traditionally, the clinical diagnosis of a respiratory disease is made from a careful clinical examination including chest auscultation. Objective analysis and automatic interpretation of the lung sound based on its physical characters are strongly warranted to assist clinical practice. In this paper, a new method is proposed to distinguish between the normal and the abnormal subjects using the morphological complexities of the lung sound signals. The morphological embedded complexities used in these experiments have been calculated in terms of texture information (lacunarity), irregularity index (sample entropy), third order moment (skewness), and fourth order moment (Kurtosis). These features are extracted from a mixed data set of 10 normal and 20 abnormal subjects and are analyzed using two different classifiers: extreme learning machine (ELM) and support vector machine (SVM) network. The results are obtained using 5-fold cross-validation. The performance of the proposed method is compared with a wavelet analysis based method. The developed algorithm gives a better accuracy of 92.86% and sensitivity of 86.30% and specificity of 86.90% for a composite feature vector of four morphological indices. Ashok Mondal, Parthasarathi Bhattacharya, and Goutam Saha Copyright © 2014 Ashok Mondal et al. All rights reserved. Frequency Selective Properties of Coaxial Transmission Lines Loaded with Combined Artificial Inclusions Thu, 23 Jan 2014 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2014/731947/ The properties of a modified coaxial transmission line by periodic inclusions will be discussed. The introduction of split ring resonators, conductor stubs, air gaps, and combination of these gives rise to new frequency selective properties, such as stopband or passband behavior, observable in planar as well as volumetric metamaterial structures. These results envisage new potential applications and implementation of devices in coaxial transmission line technology. Francisco Falcone and Javier Gil Copyright © 2014 Francisco Falcone and Javier Gil. All rights reserved. Designing a Ring-VCO for RFID Transponders in 0.18 m CMOS Process Wed, 22 Jan 2014 11:41:30 +0000 http://www.hindawi.com/journals/tswj/2014/580385/ In radio frequency identification (RFID) systems, performance degradation of phase locked loops (PLLs) mainly occurs due to high phase noise of voltage-controlled oscillators (VCOs). This paper proposes a low power, low phase noise ring-VCO developed for 2.42 GHz operated active RFID transponders compatible with IEEE 802.11 b/g, Bluetooth, and Zigbee protocols. For ease of integration and implementation of the module in tiny die area, a novel pseudodifferential delay cell based 3-stage ring oscillator has been introduced to fabricate the ring-VCO. In CMOS technology, 0.18 m process is adopted for designing the circuit with 1.5 V power supply. The postlayout simulated results show that the proposed oscillator works in the tuning range of 0.5–2.54 GHz and dissipates 2.47 mW of power. It exhibits a phase noise of −126.62 dBc/Hz at 25 MHz offset from 2.42 GHz carrier frequency. Jubayer Jalil, Mamun Bin Ibne Reaz, Mohammad Arif Sobhan Bhuiyan, Labonnah Farzana Rahman, and Tae Gyu Chang Copyright © 2014 Jubayer Jalil et al. All rights reserved. Tunable First-Order Resistorless All-Pass Filter with Low Output Impedance Wed, 22 Jan 2014 11:09:50 +0000 http://www.hindawi.com/journals/tswj/2014/219453/ This paper presents a voltage mode cascadable single active element tunable first-order all-pass filter with a single passive component. The active element used to realise the filter is a new building block termed as differential difference dual-X current conveyor with a buffered output (DD-DXCCII). The filter is thus realized with the help of a DD-DXCCII, a capacitor, and a MOS transistor. By exploiting the low output impedance, a higher order filter is also realized. Nonideal and parasitic study is also carried out on the realised filters. The proposed DD-DXCCII filters are simulated using TSMC the 0.25 µm technology. Parveen Beg Copyright © 2014 Parveen Beg. All rights reserved. Two-Step Single Slope/SAR ADC with Error Correction for CMOS Image Sensor Wed, 22 Jan 2014 10:23:31 +0000 http://www.hindawi.com/journals/tswj/2014/861278/ Conventional two-step ADC for CMOS image sensor requires full resolution noise performance in the first stage single slope ADC, leading to high power consumption and large chip area. This paper presents an 11-bit two-step single slope/successive approximation register (SAR) ADC scheme for CMOS image sensor applications. The first stage single slope ADC generates a 3-bit data and 1 redundant bit. The redundant bit is combined with the following 8-bit SAR ADC output code using a proposed error correction algorithm. Instead of requiring full resolution noise performance, the first stage single slope circuit of the proposed ADC can tolerate up to 3.125% quantization noise. With the proposed error correction mechanism, the power consumption and chip area of the single slope ADC are significantly reduced. The prototype ADC is fabricated using 0.18 μm CMOS technology. The chip area of the proposed ADC is 7 μm × 500 μm. The measurement results show that the energy efficiency figure-of-merit (FOM) of the proposed ADC core is only 125 pJ/sample under 1.4 V power supply and the chip area efficiency is 84 k μm2·cycles/sample. Fang Tang, Amine Bermak, Abbes Amira, Mohieddine Amor Benammar, Debiao He, and Xiaojin Zhao Copyright © 2014 Fang Tang et al. All rights reserved. Robust Range Estimation with a Monocular Camera for Vision-Based Forward Collision Warning System Thu, 16 Jan 2014 12:04:49 +0000 http://www.hindawi.com/journals/tswj/2014/923632/ We propose a range estimation method for vision-based forward collision warning systems with a monocular camera. To solve the problem of variation of camera pitch angle due to vehicle motion and road inclination, the proposed method estimates virtual horizon from size and position of vehicles in captured image at run-time. The proposed method provides robust results even when road inclination varies continuously on hilly roads or lane markings are not seen on crowded roads. For experiments, a vision-based forward collision warning system has been implemented and the proposed method is evaluated with video clips recorded in highway and urban traffic environments. Virtual horizons estimated by the proposed method are compared with horizons manually identified, and estimated ranges are compared with measured ranges. Experimental results confirm that the proposed method provides robust results both in highway and in urban traffic environments. Ki-Yeong Park and Sun-Young Hwang Copyright © 2014 Ki-Yeong Park and Sun-Young Hwang. All rights reserved. High-Speed Current dq PI Controller for Vector Controlled PMSM Drive Thu, 16 Jan 2014 09:37:34 +0000 http://www.hindawi.com/journals/tswj/2014/709635/ High-speed current controller for vector controlled permanent magnet synchronous motor (PMSM) is presented. The controller is developed based on modular design for faster calculation and uses fixed-point proportional-integral (PI) method for improved accuracy. Current controller is usually implemented in digital signal processor (DSP) based computer. However, DSP based solutions are reaching their physical limits, which are few microseconds. Besides, digital solutions suffer from high implementation cost. In this research, the overall controller is realizing in field programmable gate array (FPGA). FPGA implementation of the overall controlling algorithm will certainly trim down the execution time significantly to guarantee the steadiness of the motor. Agilent 16821A Logic Analyzer is employed to validate the result of the implemented design in FPGA. Experimental results indicate that the proposed current PI controller needs only 50 ns of execution time in 40 MHz clock, which is the lowest computational cycle for the era. Mohammad Marufuzzaman, Mamun Bin Ibne Reaz, Labonnah Farzana Rahman, and Tae Gyu Chang Copyright © 2014 Mohammad Marufuzzaman et al. All rights reserved. Robust Human Machine Interface Based on Head Movements Applied to Assistive Robotics Thu, 26 Dec 2013 15:30:58 +0000 http://www.hindawi.com/journals/tswj/2013/589636/ This paper presents an interface that uses two different sensing techniques and combines both results through a fusion process to obtain the minimum-variance estimator of the orientation of the user’s head. Sensing techniques of the interface are based on an inertial sensor and artificial vision. The orientation of the user’s head is used to steer the navigation of a robotic wheelchair. Also, a control algorithm for assistive technology system is presented. The system is evaluated by four individuals with severe motors disability and a quantitative index was developed, in order to objectively evaluate the performance. The results obtained are promising since most users could perform the proposed tasks with the robotic wheelchair. Elisa Perez, Natalia López, Eugenio Orosco, Carlos Soria, Vicente Mut, and Teodiano Freire-Bastos Copyright © 2013 Elisa Perez et al. All rights reserved. Electricity Usage Scheduling in Smart Building Environments Using Smart Devices Thu, 26 Dec 2013 14:19:07 +0000 http://www.hindawi.com/journals/tswj/2013/468097/ With the recent advances in smart grid technologies as well as the increasing dissemination of smart meters, the electricity usage of every moment can be detected in modern smart building environments. Thus, the utility company adopts different price of electricity at each time slot considering the peak time. This paper presents a new electricity usage scheduling algorithm for smart buildings that adopts real-time pricing of electricity. The proposed algorithm detects the change of electricity prices by making use of a smart device and changes the power mode of each electric device dynamically. Specifically, we formulate the electricity usage scheduling problem as a real-time task scheduling problem and show that it is a complex search problem that has an exponential time complexity. An efficient heuristic based on genetic algorithms is performed on a smart device to cut down the huge searching space and find a reasonable schedule within a feasible time budget. Experimental results with various building conditions show that the proposed algorithm reduces the electricity charge of a smart building by 25.6% on average and up to 33.4%. Eunji Lee and Hyokyung Bahn Copyright © 2013 Eunji Lee and Hyokyung Bahn. All rights reserved. Substrate Integrated Waveguide Cross-Coupling Filter with Multilayer Hexagonal Cavity Wed, 25 Dec 2013 10:52:39 +0000 http://www.hindawi.com/journals/tswj/2013/682707/ Hexagonal cavities and their applications to multilayer substrate integrated waveguide (SIW) filters are presented. The hexagonal SIW cavity which can combine flexibility of rectangular one and performance of circular one is convenient for bandpass filter’s design. Three types of experimental configuration with the same central frequency of 10 GHz and bandwidth of 6%, including three-order and four-order cross-coupling topologies, are constructed and fabricated based on low temperature cofired ceramic (LTCC) technology. Both theoretical and experimental results are presented. B. Wu, Z. Q. Xu, and J. X. Liao Copyright © 2013 B. Wu et al. All rights reserved. New Power Sharing Control for Inverter-Dominated Microgrid Based on Impedance Match Concept Mon, 23 Dec 2013 19:07:01 +0000 http://www.hindawi.com/journals/tswj/2013/816525/ Power flow control is one of the most important issues for operating the inverter-dominated autonomous microgrid. A technical challenge is how to achieve the accurate active/reactive power sharing of inverters. and droop control schemes have been widely used for power sharing in the past decades. But they suffer from the poor power sharing in the presence of unequal line impedance. In order to solve the problem, a comprehensive analysis of the power droop control is presented, and a new droop control based on the impedance match concept is proposed in this paper. In addition, the design guidelines of control coefficients and virtual impedance are provided. Finally, the performance evaluation is carried out, and the evaluation results verify the effectiveness of the proposed method. Herong Gu, Deyu Wang, Hong Shen, Wei Zhao, and Xiaoqiang Guo Copyright © 2013 Herong Gu et al. All rights reserved. Comparison between Phase-Shift Full-Bridge Converters with Noncoupled and Coupled Current-Doubler Rectifier Thu, 05 Dec 2013 15:51:09 +0000 http://www.hindawi.com/journals/tswj/2013/621896/ This paper presents comparison between phase-shift full-bridge converters with noncoupled and coupled current-doubler rectifier. In high current capability and high step-down voltage conversion, a phase-shift full-bridge converter with a conventional current-doubler rectifier has the common limitations of extremely low duty ratio and high component stresses. To overcome these limitations, a phase-shift full-bridge converter with a noncoupled current-doubler rectifier (NCDR) or a coupled current-doubler rectifier (CCDR) is, respectively, proposed and implemented. In this study, performance analysis and efficiency obtained from a 500 W phase-shift full-bridge converter with two improved current-doubler rectifiers are presented and compared. From their prototypes, experimental results have verified that the phase-shift full-bridge converter with NCDR has optimal duty ratio, lower component stresses, and output current ripple. In component count and efficiency comparison, CCDR has fewer components and higher efficiency at full load condition. For small size and high efficiency requirements, CCDR is relatively suitable for high step-down voltage and high efficiency applications. Cheng-Tao Tsai, Jye-Chau Su, and Sheng-Yu Tseng Copyright © 2013 Cheng-Tao Tsai et al. All rights reserved. Current Conveyor All-Pass Sections: Brief Review and Novel Solution Thu, 28 Nov 2013 12:00:42 +0000 http://www.hindawi.com/journals/tswj/2013/429391/ This study relates to the review of an important analog electronic function in form of all-pass filter’s realization using assorted current conveyor types and their relative performances, which resulted in a novel solution based on a new proposed active element. The study encompasses notable proposals during last the decade or more, and provides a platform for a broader future survey on the topic for enhancing the knowledge penetration amongst the researchers in the specified field. A new active element named EXCCII (Extra-X second generation current conveyor) with buffered output is found in the study along with its use in a new first-order all-pass section, with possible realization using commercially available IC (AD-844) and results. Sudhanshu Maheshwari Copyright © 2013 Sudhanshu Maheshwari. All rights reserved. Gm-Realization of Controlled-Gain Current Follower Transconductance Amplifier Thu, 28 Nov 2013 10:48:04 +0000 http://www.hindawi.com/journals/tswj/2013/201565/ This paper describes the conception of the current follower transconductance amplifier (CFTA) with electronically and linearly current tunable. The newly modified element is realized based on the use of transconductance cells () as core circuits. The advantage of this element is that the current transfer ratios ( and ) can be tuned electronically and linearly by adjusting external DC bias currents. The circuit is designed and analyzed in 0.35 μm TSMC CMOS technology. Simulation results for the circuit with ±1.25 V supply voltages show that it consumes only 0.43 mw quiescent power with 70 MHz bandwidth. As an application example, a current-mode KHN biquad filter is designed and simulated. Worapong Tangsrirat Copyright © 2013 Worapong Tangsrirat. All rights reserved. A Robust Variable Sampling Time BLDC Motor Control Design Based upon -Synthesis Tue, 12 Nov 2013 08:38:50 +0000 http://www.hindawi.com/journals/tswj/2013/236404/ The variable sampling rate system is encountered in many applications. When the speed information is derived from the position marks along the trajectory, one would have a speed dependent sampling rate system. The conventional fixed or multisampling rate system theory may not work in these cases because the system dynamics include the uncertainties which resulted from the variable sampling rate. This paper derived a convenient expression for the speed dependent sampling rate system. The varying sampling rate effect is then translated into multiplicative uncertainties to the system. The design then uses the popular -synthesis process to achieve a robust performance controller design. The implementation on a BLDC motor demonstrates the effectiveness of the design approach. Chung-Wen Hung and Jia-Yush Yen Copyright © 2013 Chung-Wen Hung and Jia-Yush Yen. All rights reserved. A Compact Symmetric Microstrip Filter Based on a Rectangular Meandered-Line Stepped Impedance Resonator with a Triple-Band Bandstop Response Mon, 11 Nov 2013 15:16:48 +0000 http://www.hindawi.com/journals/tswj/2013/457693/ This paper presents a symmetric-type microstrip triple-band bandstop filter incorporating a tri-section meandered-line stepped impedance resonator (SIR). The length of each section of the meandered line is 0.16, 0.15, and 0.83 times the guided wavelength (), so that the filter features three stop bands at 2.59 GHz, 6.88 GHz, and 10.67 GHz, respectively. Two symmetric SIRs are employed with a microstrip transmission line to obtain wide bandwidths of 1.12, 1.34, and 0.89 GHz at the corresponding stop bands. Furthermore, an equivalent circuit model of the proposed filter is developed, and the model matches the electromagnetic simulations well. The return losses of the fabricated filter are measured to be −29.90 dB, −28.29 dB, and −26.66 dB while the insertion losses are 0.40 dB, 0.90 dB, and 1.10 dB at the respective stop bands. A drastic reduction in the size of the filter was achieved by using a simplified architecture based on a meandered-line SIR. Rajendra Dhakal and Nam-Young Kim Copyright © 2013 Rajendra Dhakal and Nam-Young Kim. All rights reserved. Approximate Single-Diode Photovoltaic Model for Efficient I-V Characteristics Estimation Tue, 05 Nov 2013 16:43:29 +0000 http://www.hindawi.com/journals/tswj/2013/230471/ Precise photovoltaic (PV) behavior models are normally described by nonlinear analytical equations. To solve such equations, it is necessary to use iterative procedures. Aiming to make the computation easier, this paper proposes an approximate single-diode PV model that enables high-speed predictions for the electrical characteristics of commercial PV modules. Based on the experimental data, statistical analysis is conducted to validate the approximate model. Simulation results show that the calculated current-voltage (I-V) characteristics fit the measured data with high accuracy. Furthermore, compared with the existing modeling methods, the proposed model reduces the simulation time by approximately 30% in this work. Jieming Ma, Ka Lok Man, T. O. Ting, Nan Zhang, Sheng-Uei Guan, and Prudence W. H. Wong Copyright © 2013 Jieming Ma et al. All rights reserved. Control of Disturbing Loads in Residential and Commercial Buildings via Geometric Algebra Wed, 23 Oct 2013 14:53:53 +0000 http://www.hindawi.com/journals/tswj/2013/463983/ Many definitions have been formulated to represent nonactive power for distorted voltages and currents in electronic and electrical systems. Unfortunately, no single universally suitable representation has been accepted as a prototype for this power component. This paper defines a nonactive power multivector from the most advanced multivectorial power theory based on the geometric algebra (GA). The new concept can have more importance on harmonic loads compensation, identification, and metering, between other applications. Likewise, this paper is concerned with a pioneering method for the compensation of disturbing loads. In this way, we propose a multivectorial relative quality index   associated with the power multivector. It can be assumed as a new index for power quality evaluation, harmonic sources detection, and power factor improvement in residential and commercial buildings. The proposed method consists of a single-point strategy based of a comparison among different relative quality index multivectors, which may be measured at the different loads on the same metering point. The comparison can give pieces of information with magnitude, direction, and sense on the presence of disturbing loads. A numerical example is used to illustrate the clear capabilities of the suggested approach. Manuel-V. Castilla Copyright © 2013 Manuel-V. Castilla. All rights reserved. Design of UWB Monopole Antenna with Dual Notched Bands Using One Modified Electromagnetic-Bandgap Structure Thu, 19 Sep 2013 17:05:06 +0000 http://www.hindawi.com/journals/tswj/2013/917965/ A modified electromagnetic-bandgap (M-EBG) structure and its application to planar monopole ultra-wideband (UWB) antenna are presented. The proposed M-EBG which comprises two strip patch and an edge-located via can perform dual notched bands. By properly designing and placing strip patch near the feedline, the proposed M-EBG not only possesses a simple structure and compact size but also exhibits good band rejection. Moreover, it is easy to tune the dual notched bands by altering the dimensions of the M-EBG. A demonstration antenna with dual band-notched characteristics is designed and fabricated to validate the proposed method. The results show that the proposed antenna can satisfy the requirements of VSWR < 2 over UWB 3.1–10.6 GHz, except for the rejected bands of the world interoperability for microwave access (WiMAX) and the wireless local area network (WLAN) at 3.5 GHz and 5.5 GHz, respectively. Hao Liu and Ziqiang Xu Copyright © 2013 Hao Liu and Ziqiang Xu. All rights reserved. Parallel PWMs Based Fully Digital Transmitter with Wide Carrier Frequency Range Wed, 18 Sep 2013 15:58:58 +0000 http://www.hindawi.com/journals/tswj/2013/373429/ The carrier-frequency (CF) and intermediate-frequency (IF) pulse-width modulators (PWMs) based on delay lines are proposed, where baseband signals are conveyed by both positions and pulse widths or densities of the carrier clock. By combining IF-PWM and precorrected CF-PWM, a fully digital transmitter with unit-delay autocalibration is implemented in 180 nm CMOS for high reconfiguration. The proposed architecture achieves wide CF range of 2 M–1 GHz, high power efficiency of 70%, and low error vector magnitude (EVM) of 3%, with spectrum purity of 20 dB optimized in comparison to the existing designs. Bo Zhou, Kun Zhang, Wenbiao Zhou, Yanjun Zhang, and Dake Liu Copyright © 2013 Bo Zhou et al. All rights reserved. Optimized Hyper Beamforming of Linear Antenna Arrays Using Collective Animal Behaviour Mon, 22 Jul 2013 10:22:45 +0000 http://www.hindawi.com/journals/tswj/2013/982017/ A novel optimization technique which is developed on mimicking the collective animal behaviour (CAB) is applied for the optimal design of hyper beamforming of linear antenna arrays. Hyper beamforming is based on sum and difference beam patterns of the array, each raised to the power of a hyperbeam exponent parameter. The optimized hyperbeam is achieved by optimization of current excitation weights and uniform interelement spacing. As compared to conventional hyper beamforming of linear antenna array, real coded genetic algorithm (RGA), particle swarm optimization (PSO), and differential evolution (DE) applied to the hyper beam of the same array can achieve reduction in sidelobe level (SLL) and same or less first null beam width (FNBW), keeping the same value of hyperbeam exponent. Again, further reductions of sidelobe level (SLL) and first null beam width (FNBW) have been achieved by the proposed collective animal behaviour (CAB) algorithm. CAB finds near global optimal solution unlike RGA, PSO, and DE in the present problem. The above comparative optimization is illustrated through 10-, 14-, and 20-element linear antenna arrays to establish the optimization efficacy of CAB. Gopi Ram, Durbadal Mandal, Rajib Kar, and Sakti Prasad Ghoshal Copyright © 2013 Gopi Ram et al. All rights reserved. Efficient and Accurate Optimal Linear Phase FIR Filter Design Using Opposition-Based Harmony Search Algorithm Mon, 10 Jun 2013 08:20:04 +0000 http://www.hindawi.com/journals/tswj/2013/320489/ In this paper, opposition-based harmony search has been applied for the optimal design of linear phase FIR filters. RGA, PSO, and DE have also been adopted for the sake of comparison. The original harmony search algorithm is chosen as the parent one, and opposition-based approach is applied. During the initialization, randomly generated population of solutions is chosen, opposite solutions are also considered, and the fitter one is selected as a priori guess. In harmony memory, each such solution passes through memory consideration rule, pitch adjustment rule, and then opposition-based reinitialization generation jumping, which gives the optimum result corresponding to the least error fitness in multidimensional search space of FIR filter design. Incorporation of different control parameters in the basic HS algorithm results in the balancing of exploration and exploitation of search space. Low pass, high pass, band pass, and band stop FIR filters are designed with the proposed OHS and other aforementioned algorithms individually for comparative optimization performance. A comparison of simulation results reveals the optimization efficacy of the OHS over the other optimization techniques for the solution of the multimodal, nondifferentiable, nonlinear, and constrained FIR filter design problems. S. K. Saha, R. Dutta, R. Choudhury, R. Kar, D. Mandal, and S. P. Ghoshal Copyright © 2013 S. K. Saha et al. All rights reserved. PSO Based PI Controller Design for a Solar Charger System Mon, 13 May 2013 15:19:38 +0000 http://www.hindawi.com/journals/tswj/2013/815280/ Due to global energy crisis and severe environmental pollution, the photovoltaic (PV) system has become one of the most important renewable energy sources. Many previous studies on solar charger integrated system only focus on load charge control or switching Maximum Power Point Tracking (MPPT) and charge control modes. This study used two-stage system, which allows the overall portable solar energy charging system to implement MPPT and optimal charge control of Li-ion battery simultaneously. First, this study designs a DC/DC boost converter of solar power generation, which uses variable step size incremental conductance method (VSINC) to enable the solar cell to track the maximum power point at any time. The voltage was exported from the DC/DC boost converter to the DC/DC buck converter, so that the voltage dropped to proper voltage for charging the battery. The charging system uses constant current/constant voltage (CC/CV) method to charge the lithium battery. In order to obtain the optimum PI charge controller parameters, this study used intelligent algorithm to determine the optimum parameters. According to the simulation and experimental results, the control parameters resulted from PSO have better performance than genetic algorithms (GAs). Her-Terng Yau, Chih-Jer Lin, and Qin-Cheng Liang Copyright © 2013 Her-Terng Yau et al. All rights reserved. A High Voltage Ratio and Low Ripple Interleaved DC-DC Converter for Fuel Cell Applications Sun, 23 Dec 2012 16:23:56 +0000 http://www.hindawi.com/journals/tswj/2012/896508/ This paper proposes a high voltage ratio and low ripple interleaved boost DC-DC converter, which can be used to reduce the output voltage ripple. This converter transfers the low DC voltage of fuel cell to high DC voltage in DC link. The structure of the converter is parallel with two voltage-doubler boost converters by interleaving their output voltages to reduce the voltage ripple ratio. Besides, it can lower the current stress for the switches and inductors in the system. First, the PSIM software was used to establish a proton exchange membrane fuel cell and a converter circuit model. The simulated and measured results of the fuel cell output characteristic curve are made to verify the correctness of the established simulation model. In addition, some experimental results are made to validate the effectiveness in improving output voltage ripple of the proposed high voltage ratio interleaved boost DC-DC converters. Long-Yi Chang, Kuei-Hsiang Chao, and Tsang-Chih Chang Copyright © 2012 Long-Yi Chang et al. All rights reserved.