Design of Broadband Band-Pass Filter with Cross-Coupled Line Structure

This paper presents a broadband band-pass filter with cross-coupled line structure. The cross-coupled line structure is composed of the parallel coupled lines and an open stub. It can be analyzed by the odd- and even-mode method due to its symmetric structure. There are three transmission poles in the passband and two transmission zeros out of passband. Then, the influence of the impedance parameters on the transmission zeros and transmission poles are analyzed. Then, the physical parameters of the proposed band-pass filter are given. And using HFSS for simulation and optimization, the final insertion loss and return loss of filter are obtained. The simulation and measurement results are in good agreement, which validates the design idea.