COMPACT QUAD-BAND BPF BASED ON STUB LOADED DOUBLE-RING RESONATOR

摘要

A compact quad-band band-pass filter (BPF) based on a single stub loaded double-ring resonator (SL-DRR) is presented in this article. The proposed SL-DRR, which can introduce four narrow passbands simultaneously, is investigated using even/odd mode analysis. As an example, a BPF centered at 1.57, 2.8, 5.2, and 5.9 GHz is designed and it achieves a more than 45% size reduction compared to the designs reported in open literature. Theoretical and simulated results are presented, which are in good agreement with the measured ones.