A cavity triple-mode filter with excitation of L-shape model

© 2018 IEEE. A triple-mode cavity filter with narrow passband realized in a single rectangular metal cavity without any tune crews, coupling apertures, iris, and corner cuts is proposed in this paper, while three resonant modes are classified as a TM mode and a pair of TE modes, which are excited by two metal probes in one single cavity. At both the upper and lower stop-bands, two transmission zeros are created to achieve a considerable out-of-band suppression. To prove the concept, a prototype is fabricated by using the silver plated aluminum technology demonstrating a measured fractional bandwidth of 3.6% at the center frequency of 2.53 GHz. The measured and simulated results are presented in good agreement