Improvement of compactness of low pass and band pass filter using a simple combination of cross‐defected ground structure and a discontinuous microstrip line

Abstract

AbstractThis article presents a method to reduce the size of LPF/BPF using defected ground structure (DGS). The DGS filter structure employs two cross‐slots etched in the ground plane. To validate the feasibility of the proposed design method, a low‐pass filter with 0.1‐dB ripple is designed, fabricated, and measured. Then a simple technique to transform the designed BPF to a LPF was presented. Additionally, a new suspended Layer's technique will be used with DGS in order to reduce more the size and to suppress the second harmonic in reject band. The second order band pass filter was designed using the proposed technique and their simulation results confirmed the validity of the technique. Simulated and measured results of the proposed filters are presented and show good agreements. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1191–1195, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24291