Design and Analysis of Compact SIW Bandpass Filter using DGSDMS Technique for Satellite Applications

Abstract

This letter proposes a new compact substrate integrated waveguide based bandpass filter for
satellite application. First SIW BPF is designed by tapered via transition to provide a smooth
transition from microstrip line to SIW cavity with minimal reflection and better S11
performance. The stop band performance of the proposed filter is improved by introducing a
two square head DGS connected by U-slot on the bottom ground plane which introduces
transmission zeros in upper stopband. DMS is made by etching two horizontal slots on the
top of the SIW cavity in order to provide finite passband and to suppress undesired harmonic
response. The filter with center frequency of 7GHz and fractional bandwidth of 2.8% is
developed on the Rogers substrate with dielectric constant of 3.5 and substrate thickness of
0.5mm. By combining the concept of DGS-DMS, the proposed filter exhibits very low
insertion loss of 0.02dB, return loss >20dB and compact size. The structure is simulated and
analyzed by using Advanced Design software.