In this paper, the design of a fully integrated DC-5 GHz NMOS single-pole double throw (SPDT) transmit/receive (T/R) switch for radio-frequency (RF) applications in a 0.25-mum SiGe BiCMOS/RFCMOS technology, is presented. The switch insertion loss is < 1.4 dB, the isolation is > 30.1 dB, all over the 0-5 GHz band, and the return loss is > 19.9 dB in the 0.8-1 GHz band and is >10.2 dB in the 0-0.8 GHz and 1-5 GHz bands. (C) 2003 Elsevier B.V. All rights reserved.