Low-spurious-response coaxial-line BPF with saucer-loaded stepped-impedance resonators designed with mode-matching technique

Abstract

A novel stepped-impedance resonator with a thin metal saucer is proposed in order to reduce spurious-response levels in a coaxial-line bandpass filter (BPF). In designing the BPF, the mode-matching technique is employed for fast and accurate calculation of coaxial-line discontinuities. A prototype BPF obtains a spurious-response level of less than ؊55 dB in the frequency band from 2f 0 to 9f 0 , where f 0 is the pass-band center frequency.