A CMOS transmit-receive (T/R) switch design for ultrawideband (UWB) wireless applications is presented. A shunt inductor is adopted in the T/R switch signal path to improve the insertion loss (IL) and work as electrostatic discharge (ESD) protection device. Two bypassing switches at the gate of the main switching transistors provide additional isolation. Control voltage as low as 1.2V is applied to handle the T/R switch operation. Implemented in UMC 0.13/spl mu/m MMRF CMOS technology, the measured results show an IL of 0.78-0.99dB in the receive (RX) mode and an isolation from TX port to RX port higher than 30.8dB in the transmit (TX) mode in the 3.1-4.8GHz frequency range. The measured ESD rating is 3kV HBM. The T/R switch is designed for monolithic integration with UWB RF front-end building blocks. The on-chip inductor eliminates the need of an off-chip one for the wideband matching network.