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Active and Passive Electronic Components
Volume 2007, Article ID 93548, 5 pages
Research Article

Design of a Broadband Parallel-Coupled Microstrip Filters without Spurious Resonances

Faculty of Engineering, Mansoura University, Mansoura, Egypt

Received 5 March 2007; Accepted 21 November 2007

Academic Editor: Ashok K. Goel

Copyright © 2007 Maher M. Abd-Elrazzak. 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.


A design of parallel-coupled microstrip bandpass filters without spurious resonance is presented. Two different techniques are used to eliminate this response at twice the passband frequency (2fo). The first one is based on usage of suspended substrate, while the second is carried out by shorting the parallel-coupled lines to the ground plane through two shorting walls. The numerical results show that a broadband filter can be obtained by the suppression of the spurious response. The finite difference time domain (FDTD) with the perfect matched layer (PML) is used in the present analysis. The obtained results are compared with the available published data and good agreements are found.