1.866–2.782-GHz Reconfigurable Filtering Single-Pole-Multithrow Switches Based on Evanescent-Mode Cavity Resonators

In this article, novel reconfigurable filtering single-pole-multithrow (SPMT) switches based on the evanescent-mode cavity (EVA) are proposed. The design incorporates varactors between two EVA resonators. By controlling the varactor capacitance value, the coupling coefficient between resonators can be set to be zero or desired value which allows the corresponding signal path to be in OFF-state with high isolation or in ON-state with bandpass filter response. Based on this technique, filtering SPMT switches can be achieved with reconfigurable frequencies. Moreover, each filtering-switch path shares two common resonators with others, which significantly reduce the filter size and make the proposed SPMT very compact. A filtering single-pole-double-throw (SPDT) switch and a filtering single-pole-5-throw (SP5T) switch were designed, fabricated, and measured to demonstrate the proposed technique. These filtering switches can be continuously tuned from 1.953-2.782 and 1.866-2.257 GHz, respectively, with isolation better than 47.2 and 36.1 dB, respectively. Good agreement is obtained between simulated and measured results.