Characteristic Improvement of Circular Waveguide BPF Using Artificial Dielectric Resonators

Artificial dielectric material made of FR4 Epoxy dielectric was successfully realized. This material served as a resonator in a circular waveguide bandpass filter (BPF), which caused the characteristic improvement of BPF. The observation of resonator is based on two things, the distance between resonators and the thickness of each resonator. The simulation result shows the increase of working frequency of BPF for the distance between resonators, while the thickness of each resonator produce the opposite trend in working frequency. The realization of artificial dielectric resonator is conducted using FR4 Epoxy dielectric which is inserted by cylindrical conductors in a certain amount. The insertion of conductors would likely reduce the working frequency of BPF. The result decreases in the working frequency of BPF from initially 4.6GHz to be 3.9GHz with the value of S11 about -19 dB.