Design and Application of Coupled Line Cross-Shaped Resonator in Band-pass Filter

摘要

A coupled line cross-shaped resonator (CLCSR) is proposed, which consists of four parallel coupled lines. By using even- and odd-mode approach, this resonator is characterized and designed to build up a wide band-pass filter. There are three transmission poles in the pass-band and two transmission zeros out of the pass-band. The positions of the transmission zeros are fixed. The transmission poles are determined and adjusted by the parameters: z(1), z(2), k(1), and k(2). Then two coupled line cross-shaped resonators are cascaded to realize a wide band-pass filter. The sharper selectivity and better performance can be obtained by cascading two CLCSRs. Good S-parameters are achieved as demonstrated in both simulated and measured results.