Design of a Compact UWB Filter With High Selectivity and Superwide Stopband

摘要

This letter presents a design of compact ultra-wideband bandpass filter (BPF) with high selectivity and superwide stopband. Three resonant modes from the multiple-mode resonator (MMR) based on half-mode substrate integrated waveguide (HMSIW) structure and four resonant modes from a pair of electromagnetic bandgap loaded parallel-coupled lines can constitute a wideband performance. Superwide stopband can be achieved and two transmission zeros are realized on both sides of the passband to improve the filter selectivity. A prototype of the BPF operating from 3.1 to 10.4 GHz with an extremely broad stopband region from 10.7 to 24 GHz and a rejection level of 15 dB is demonstrated in the measured results.