Design of quasi-elliptic bandpass filter for substrate integrated waveguide (SIW) using cross coupling technique

Abstract

This paper proposes a quasi-elliptic band pass filter in substrate integrated waveguide (SIW) by using cross coupling technique to produce transmission zeros (TZs) at both sides. Finally, a fourth pole SIW quasi-elliptic filter at 5.75 GHz is designed in single layer substrate. Simulation results show that the filter has a center frequency of 5.75 GHz with the bandwidth of 100 MHz. The minimum insertion loss in the passband is 0.3 dB, and the return loss is better than 20 dB. Due to the TZs, the SIW filter has rapid transition performance at both lower and upper sidebands, good selectivity is achieved, while the SIW filter presents a very compact implementation and good spurious rejection.