Table of Contents
International Journal of Microwave Science and Technology
Volume 2012 (2012), Article ID 473030, 6 pages
http://dx.doi.org/10.1155/2012/473030
Research Article

A Simple Microstrip Bandstop Filter Using Cross-Coupling Stubs

Department of Electronic Engineering, City University of Hong Kong, Hong Kong

Received 2 March 2012; Revised 26 June 2012; Accepted 10 July 2012

Academic Editor: Samir Trabelsi

Copyright © 2012 Leung Chiu and Quan Xue. 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.

Abstract

This paper presents an alterative implementation of a shunt open-circuited stub for multilayer microwave circuit. With making use of the proposed implementation, a simple and compact bandstop filter with a district bandstop characteristics and a first spurious at the third harmonic is proposed. The proposed filter exhibits about 12.5% fractional bandwidth of −10 dB signal rejection at the center frequency of 2.04 GHz and flat group delay at the pass bands. Besides, by cascading a number of the proposed bandstop filters designed at the different frequencies, multiband bandstop filters can be easily realized. A dual- (tri-) band design at the center frequencies of 2 GHz and 3 GHz (and 4 GHz) is designed, realized, and measured. The proposed bandstop filter well suits the nowadays multilayer and compact radio frequency integrated circuit design.