Compact dual‐mode dual‐band HMSIW bandpass filters using source–load coupling with multiple transmission zeros.

Compact dual‐mode dual‐band bandpass filters (BPFs) with multiple transmission zeros (TZs) using over‐mode half‐mode substrate integrated waveguide (HMSIW) resonators are presented. Each passband built by TE001 or TE201 has three TZs introduced by source–load coupling and low‐/high‐order mode cross‐coupling between TE001 and TE201 to improve the frequency‐selectivity. The equations that determined the TZs are built. Perturbation slots realise the independent‐control of frequency ratio. Dual‐mode dual‐band BPFs are designed, fabricated and measured, and the simulated results agree with the measured results well. [ABSTRACT FROM AUTHOR]