Low‐Loss Differential SPST Switch With Filtering Response and Common‐Mode Suppression

ABSTRACT In this paper, a novel low‐loss differential switch with filtering response and common‐mode (CM) suppression is proposed for RF communication system. The single‐pole single‐throw (SPST) switch toggles ON and OFF states of the switch by controlling the voltage to PIN diodes loaded on the feeding transmission slotline. Microstrip‐to‐slotline transition provides intrinsic CM suppression for differential switch. The frequency selectivity is achieved by using modified dumb‐belled slotline resonator, and the design process of its resonant operating mechanism is provided. The fabricated and measured differential SPST switch prototype exhibits bandpass filtering response with low insertion loss under the ON state. For the OFF state of the differential SPST switch, it can demonstrate wideband rejection characteristics. More importantly, CM noises can be effectively suppressed in this design.