Miniaturized Dual-Band Filtering Switch Based on Multi-Mode Dielectric Resonator

This paper presents a dual-band filtering switch based on a single quad-mode dielectric resonator (DR). For the ON-state, the four modes are excited by the planar microstrip lines to construct the dual-band filtering response, leading to miniaturized size. Thanks to the quad-mode orthogonality, the two passband could be designed independently. Besides, the diodes are turned off in this case, avoiding the additional loss introduced into passbands. For the OFF-state, all the four modes are eliminated via the symmetrical feeding structure, resulting in high isolation. For verification, a prototype is fabricated and tested. Low loss dual-band filtering response with high selectivity and high isolation are both exhibited with miniaturized size, supporting the proposed method.