A compact tri‐band filter based on a dual‐capacitively loaded triple‐mode substrate integrated waveguide resonator

Abstract

This letter presents a compact tri‐band filter using a dual‐capacitively loaded (DCL) substrate integrated waveguide (SIW) triple‐mode resonator. The frequencies of TE101, TE102, and TE103 are shifted lower by the capacitive loading effect, which is achieved by the DCL structure. A compact tri‐band example filter is then built by using two DCL triple mode SIW resonators. Following that, seven transmission zeros are generated to improve filter selectivity by vertical coupling of two cavities. The area of the filter occupies only 0.46 λg2. The measured results demonstrate that this compact tri‐band filter has the advantages of flexible control of passbands, easy interconnection with other planar radio frequency components, making it promising for millimeter wave implementations and 3D‐integrated systems.