International Journal of Antennas and Propagation

In this work, a dual-port antenna system is simulated and fabricated for cognitive radio (CR) application. The proposed system comprises a tapered-fed monopole ultra-wideband (UWB) sensing antenna and a dual-narrowband (NB) communicating antenna. For miniaturization, the UWB sensing antenna is placed on the front side of the communicating antenna. The sensing operation takes place over 2.1–12 GHz. The E-shaped dual-band antenna operates at 3.9 GHz and 6.04 GHz. The envelope correlation coefficient (ECC) and isolation are measured to be lower than 0.12 and greater than 18 dB, respectively, within the range of acceptable values for both parameters. The antenna prototype was fabricated and tested experimentally to confirm the simulation’s findings. The outcomes of both the simulation and the testing revealed a definite consistency. This work gives a miniaturized model and good isolation, which is appropriate for C-band applications.

Microstrip antenna arrays are proposed in this paper for the customer premise equipment (CPE) applications in the frequency range 1 (FR1) of the 5^th generation (5 G) mobile networks. The proposed antenna arrays consist of three FR4 substrates. Antenna elements and feeding networks are optimized separately through parameter studies and then combined to form the proposed antenna arrays. Bandwidth-enhancing parasitic elements on the top substrate are broadside coupled to the microstrip antennas in the middle substrate, which are probe-fed by the microstrip feeding network using Wilkinson power dividers realized in the bottom substrate through the ground plane and the stud supporting air layer between the lower two substrates. Two antenna arrays, with four and eight antenna elements, are proposed for different gain specifications, 10 dBi and 12 dBi, respectively. Bandwidths of 10-dB return loss for both arrays fully covered the 5 G n78 frequency band (3.3–3.8 GHz). 20 dB isolation between antenna elements can also be achieved using the proposed layouts with rotated elements. The dimensions, radiation gain, and efficiency of the proposed antenna units, four-element array, and eight-element array are 65 × 65 × 11.4, 115 × 115 × 11.4, and 115 × 215 × 11.4 mm³, 6.2, 10.5, and 13 dBi, 74%, 56%, and 50%, respectively. The proposed antenna arrays exhibit the advantages of simple, low-cost, low-profile, and high-gain characteristics, which is potentially applicable to 5 G CPE outdoor unit (ODU)-related devices.

The electromagnetic radiation sensitivity of the electric explosive device (EED) and its installed use state is closely related to the size of the equipment and radiation field strength constraints. The use of the traditional all-level electromagnetic radiation method for the effect of the actual installed EED test in the electromagnetic environment simulation encountered a technical bottleneck. The microwave band is difficult to effectively assess through the current standing wave distribution and skin effect. The temperature rise of the EED bridge wire has no relationship with the frequency of the electromagnetic wave. In this paper, through the analysis of the electromagnetic effect mechanism of the EED, the coupled power model of electromagnetic irradiation of the EED is obtained, and the relationship between the temperature rise of the bridge wire of the EED and the electric field strength model is established. Under the action of high-frequency continuous waves, the electromagnetic effect of the device is tested to verify the correctness of the mechanism analysis of the electromagnetic effect of the device under the action of continuous waves. The results provide crucial technical support for the electromagnetic protection of the device under the harsh electromagnetic environment of the battlefield.

In this paper, a low sidelobe feeding network has been developed utilizing the louver-shaped defected ground structure (DGS). By adjusting the louver-shaped DGS, the output amplitude and phase of the corresponding ports can be altered, minimizing deviations from theoretical values. This enables antenna arrays equipped with this feeding network to more easily achieve low sidelobe performance. The impact of the louver-shaped DGS on the amplitude and phase of each port in the power divider within the feeding network is analyzed, and a 16-channel feeding network incorporating the louver-shaped DGS has been designed, fabricated, and then measured. The test results indicate that the performance of the line-feeding network is effectively improved by designing and adjusting the louver-shaped DGS. Through the debugging procedure, the amplitude deviation of the feeding network has been reduced from ±0.45 dB to ±0.2 dB, while the phase deviation of the feeding network has been reduced from ±8° to ±2.5°, and the maximum value of the first sidelobe has been reduced from −24.2 dB to −28.1 dB.

A small, orthogonally polarized, ultra-wideband (UWB), four-port multiple-input multiple-output (MIMO) printed antenna is presented in this study. The envisioned antenna is built up of four microstrip fractal-based circular patch elements, each of which is fed by a microstrip line with a 50-ohm impedance. The use of a defective ground plane allows for the ultra-wideband frequency response to be obtained. In order to achieve maximal isolation, the amount of surface current that flow between the antenna’s four components is limited by arranging radiating elements orthogonally. The four-port MIMO system is printed on a FR4 substrate with a loss tangent of 0.02 and an overall dimension of 20 × 30 × 1.6 mm³. A port-to-port isolation of less than 25 dB was achieved as a consequence of this orthogonal orientation of antenna elements, and the impedance bandwidth is achieved up to 158% (3.1–12 GHz). The suggested ultra-wideband multiple-input multiple-output (UWB-MIMO) antenna achieved a maximum gain of 8 dBi over the operational frequency range (3.1–12 GHz); the findings that were measured and those that were simulated accord with one another rather well. The findings also give an overall strong diversity performance, with the ECC < 0.25, DG > 9.9, and CCL < 0.2 values all being within acceptable ranges.

Image advertising is widely used by companies to advertise their products and increase awareness of their brands. With the constant development of image generation techniques, automatic compositing of advertisement images has also been widely studied. However, the existing algorithms cannot synthesise consistent-looking advertisement images for a given product. The key challenge is to stitch a given product into a scene that matches the style of the product while maintaining a consistent-looking. To solve this problem, this paper proposes a new two-stage automatic advertisement image generation model, called Advertisement Synthesis Network (ASNet), which explores a two-stage generation framework to synthesise consistent-looking product advertisement images. Specifically, ASNet first generates a preliminary target product scene using Pre-Synthesis and then extracts scene features using Pseudo-Target Object Encoder (PTOE) and true target features using Real Target Object Encoder (RTOE), respectively. Finally, we inject the acquired features into the pretrained diffusion model and reconstruct them in the preliminary generated target goods scene. Extensive experiments have shown that the method achieves better results in all three performance metrics related to the quality of the synthesised image compared to other methods. In addition, we have done a simple and preliminary study on the effect of synthetic advertisement images on real consumers’ purchase intention and brand perception. The results of the study show that the advertisement images synthesised by the model proposed in this paper have a positive impact on consumer purchase intention and brand perception.