Compact quasi‐elliptic SIR‐SIW filter with multiple transmission zeros

Abstract

Abstract In this paper, a compact quasi‐elliptic stepped impedance resonator‐substrate integrated waveguide (SIR‐SIW) bandpass filter with multiple transmission zeros (TZs) has been proposed. The SIR‐SIW filter consists of SIW cavity and SIR. The employment of SIR makes it possible to realize multiple energy coupling paths within a compact area for introduction of multiple TZs. The SIW is used for its high Q, low loss characteristics. Besides, two TZs are introduced by the SIW. Including energy coupling path between source and load, totally four TZs besides the passband are realized. A miniature (0.3 λg 2 ) four‐pole, four‐transmission zero filter with high selectivity is realized. Experimental verification is provided and a good agreement has been found between simulation and measurement.