A High Power CMOS Differential T/R Switch using Multi-section Impedance Transformation Technique

A high-power single-pole-double-throw (SPDT) antenna switch using a differential architecture and a multisection impedance transformation technique is demonstrated in a standard 0.18-mu m CMOS process. The differential architecture prevents unwanted channel formation of OFF-state Rx switch transistors by relieving the voltage swing over the Rx switch devices. In addition to this architecture, impedance transformation technique helps to reduce the voltage swing even more, contributing to significant enhancement of power handling capability. A loss of the whole design block including switch and matching networks has been analyzed, considering the integration issue of the front-end circuitries. The measured performance of the differential switch shows input 1-dB compression point (P1dB) of 33.8 dBm with insertion losses of 0.5 dB and 1.1 dB for Tx and Rx modes at 1.9 GHz, respectively.