Double Resonator Topology for High Isolation and Low Insertion Loss in SPDT Switch

In this paper Double Resonator Topology is used to achieve high isolation and low insertion loss in single pole double through (SPDT) switch. This SPDT switch is based on GaAs MESFET and operates in the band of 8 to 11 GHz. This circuit is tuned to give optimum very high isolation and low insertion loss in 9-10 GHz frequency band. It uses one series and three shunt branches. One series and one shunt branch capacitances are resonated out with parallel inductance. This circuit is fabricated and performance measured. The measured performance of this MMIC SPDT switch has insertion loss lower than 2 dB and isolation better than 46 dB in 9-10 GHz and insertion loss lower than 2.2 dB and isolation better than 42 dB in 8-11 GHz. This circuit has to be integrated with other component to demonstrate X-band core chip.