In this thesis, a 2.4GHz single-pole double-throw (SPDT) transmit/receive (T/R) switch using the asymmetric lightly-doped-drain (LDD) MOSFET in the shunt branch is designed to verify the improvement of power-handling capability. The asymmetric device has a nearly twice drain-source breakdown voltage (BVdss) than the conventional transistor. Measurement results show that the proposed asymmetric-MOS switch has >2 dBm improvement in 1-dB input power compression point (Pin,1dB) than the conventional topology and also has a low insertion losses of 0.62 and 0.94 at 2.4 and 5.8 GHz, respectively. These results reveal the potential of the asymmetric transistor for high-power circuit designs.