Absorptive SPDT switch design using cascaded switchable parallel-coupled stub resonator and switchable radial stub resonator

An absorptive Single Pole Double Throw (SPDT) switch using cascaded switchable parallel-coupled stub resonator and switchable radial stub resonator is proposed in this paper. By using mathematical model, theories of the switchable resonators are discussed. The switchable resonators are reconfigured between bandstop and allpass response in the absorptive SPDT switch design. The allpass response is operated in wide bandwidth centered at resonant frequency. Frequency spectrum in 3.5 GHz band has been chosen to demonstrate the design where the targeted application is Time Division Duplex (TDD) switching in wideband wireless data communication systems. The proposed absorptive SPDT switch is simulated in an electronic design automation software for analysis in terms of insertion loss, return loss and isolation. Result in simulation shows less than 2 dB of insertion loss, more than 14 dB of return loss at absorptive ports and more than 39 dB of isolation from 3.4 to 3.6 GHz.