A dual mode wideband bandpass filter based on ring structure

Abstract

In this paper, a dual mode wideband bandpass filter based on ring structure is designed. By means of odd-even mode analytical method, the dual-mode resonator is composed of a short-ended resonator with centrally loaded inductive stub. Based on the literature [5], a band-pass filter is designed. The use of a ring structure achieves the purpose of broadband band-pass, strong source-and-load coupling is achieved, which improves the in-band return loss. Using 3D electromagnetic simulation software HFSS, A third-order band-pass filter was designed on a single-layer Rogers 5880 dielectric, and its work center frequency is 5.93 GHz, passband range is from 4.41 GHz to 7.45 GHz, 3dB relative bandwidth is 51%, stopband suppression is better than 25 dB. The measured results shows that the in-band return loss is better than -10 dB, insertion loss about 1.15 dB, stopband suppression on more than 45 dB, the stopband suppression over 25 dB.