Design of Dielectric Waveguide Filter Based on Sector-Shaped Dual-Mode Resonators

A novel sector-shaped dual-mode dielectric waveguide resonator (DWR) is proposed in this letter and utilized to design a bandpass filter. Two tuning blind holes and a through hole were fabricated at the base of the resonator. The tuning blind holes were employed to independently adjust the resonant frequencies of the dual modes, while the through hole was strategically implemented to modulate the coupling strength between these modes. The proposed filter is composed of two single-mode resonators and two dual-mode resonators, the magnitude of the intercavity coupling coefficient is predominantly governed by the geometric parameters of the coupling window, enabling precise tuning through window dimension optimization. The filter was ultimately simulated, fabricated, and experimentally tested, thereby validating the feasibility of the proposed design. The fabricated dual-mode resonator filter demonstrates a center frequency of 3.7GHz with a 200MHz (7.0% 3-dB fractional bandwidth), achieving both compact size and wide bandwidth.