Modified dual-mode double-ring resonators for wide band-pass filter design

A novel design of a dual-mode resonator with modified double rings structure for a wide band-pass filter is presented. Based on the mode chart and double rings resonator, modified double rings comprising three half rings are proposed. In addition each ring exhibits dual-mode responses, those rings determine the whole operating band; i.e. the smaller/larger rings depict the upper/lower frequencies of the pass-band and construct the flat of response for wideband applications. This is an alternative approach to achieve performance of low insertion loss, wide pass-band and sharp rejection band. Experimental and simulation results are presented and discussed.