Dual-band bandpass filter using centrally coupled resonators (CCRs)

Abstract

In this paper, a compact dual-band bandpass filter using novel centrally coupled resonators (CCRs) is presented. The proposed CCR is composed of a meandered microstrip line with a centrally coupled section and two lumped capacitors, which are loaded at the ends of the coupled lines. Based on the theoretical analysis, a key merit of the proposed resonator is found that both even- and odd-mode resonances can be separately controlled by altering the values of the relative loading capacitors. Benefitting from this feature, a dual-passband filter with two independent operating frequencies can be designed and a sample topology is demonstrated. The measured results exhibit good agreement with the full-wave simulation results, validating the proposed design concept.

Acknowledgment

This work is mainly supported by the National Natural Science Foundation of China (NSFC) under Project 61201072 and 61271086.