Study of artificial dielectric resonator with anisotropic permittivity encapsulated in a circular waveguide and its filter application

The property of artificial dielectric resonators with anisotropic permittivity is studied. The study includes the investigation of resonant frequency and coupling coefficient between two resonators in a metal circular waveguide, theoretically and experimentally. Artificial dielectric resonator that assigned to excite a TE_01δ mode selectively is fabricated by lamination of 2 open-ring metal strips etched on a printed circuit board. The resonant frequency and coupling coefficient of artificial dielectric resonators encapsulated in a circular waveguide are analyzed, and then compared with the experimental result. As a microwave application, a circular waveguide bandpass filter (BPF) using two artificial dielectric resonators is demonstrated. A two-stage prototype BPF with the center frequency of 2.98 GHz, bandwidth of 115 MHz, and insertion loss of 1.8 dB is successfully realized as a trial.