A K-band dual-mode radar transmitter is implemented with 0.13-mu m CMOS technology, which supports both FMCW and UWB radar operations. A dual-functional block is proposed to achieve efficient dual-mode operation without additional paths and switches. It is switched between a pulse former and a differential amplifier for UWB and FMCW modes, respectively. As a result, the transmit signal can become either a linearly frequency-modulated signal or a time-slotted pulse signal according to the selected mode. It showed performance comparable to that of previously reported transmitters despite the fact that it operates in dual modes