This paper presents two fully integrated CMOS transmit/receive (T/R) switches with improved body-floating operations. The first design exploits an improved transistor layout with asymmetric drain–source region, which reduces the drain–source feed-through for body-floated RF switches. In the second design, a switched body-floating technique is proposed, which reconfigures the body-floating condition of a switch transistor in the ON and OFF states. Both designs are fabricated in a standard 0.13-µm triple-well CMOS process.With regard to 2-dB insertion loss, the switch with asymmetric drain–source achieves 28-GHz bandwidth, which is among the highest reported frequencies for CMOS T/R switches. The bandwidth of the switched body-floating design is 16.6 GHz. There is approximately 5 dB better isolation obtained in the switched body-floating design. With the resistive double-well body-floating technique, 26.5- and 25.5-dBm input 1-dB compression point (P 1dB) are obtained, respectively. Both designs consume only 150 µm X 100 µm die area. The demonstrated T/R switches are suitable for high-frequency and wideband transceivers.