Broadband Single-Stage Models for Microwave Band-Pass Filters

A single-stage expandable equivalent circuit is proposed to model a microwave band-pass filter up to several times its passband frequency. The equivalent circuit adopts a modified T-equivalent network to achieve an extremely large bandwidth. The modeled results for a 2.4 GHz WLAN bandpass filter fabricated in LTCC technology demonstrate good agreement with the measured results over a frequency range up to 8.5 GHz. Such a broadband model can be used to accurately predict the suppression of harmonics and interferences in system simulation of wireless front-end modules