Table of Contents
International Journal of Microwave Science and Technology
Volume 2011, Article ID 812078, 9 pages
Research Article

A Dual-Band Band-Pass Filter with Overlap Step-Impedance and Capacitively Loaded Hairpin Resonators for Wireless LAN Systems

Department of Electrical Engineering, Faculty of Engineering, King Mongkut's University of Technology North Bangkok, 1518 Pibulsongkram Road, Bangsue, Bangkok 10800, Thailand

Received 10 November 2010; Revised 1 February 2011; Accepted 1 March 2011

Academic Editor: Yo Shen Lin

Copyright © 2011 P. Chomtong et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper presents a dual-band band-pass filter using modified cross-coupled step-impedance and capacitively loaded hairpin resonators for WLAN systems. The proposed filter has been designed to operate at a fundamental frequency of 2.4 GHz and the first harmonics frequency of 5.2 GHz. The techniques of step impedance and load capacitor are combined in the design of the proposed filter. In particular, the techniques of modified cross-coupling and overlap resonators are applied to improve the response of insertion losses 𝑆 2 1 at the first harmonic frequency of 5.2 GHz. The simulated and experimental results of insertion losses and return losses are better than 3 dB and 20 dB, respectively, at the operating frequencies.