Dielectric-Loaded Miniaturized Cavity Bandpass Filter with Improved Power Capacity

Abstract

A novel design method of dielectric-loaded miniaturized cavity bandpass filter is presented in this paper. The proposed cavity resonator is filled with dielectric material to improve power capacity, while realizing the miniaturization of the filter. To validate our proposal, a bandpass filter with a center frequency of 1475 MHz and bandwidth of 90 MHz is designed, fabricated, and measured. The measured insertion loss is ≤0.49 dB and return loss is ≥20 dB in 1430 MHz~1520 MHz. The measured upper stopband rejection is greater than 48.5 dB in 1575 MHz~2700 MHz. The measured results are in good agreement with the simulation, which verifies the effectiveness and practicability of the method. The metal cavity bandpass filter, filled with dielectric material, is reduced by 25% in the thickness direction and its power capacity is increased by 45.8%.