In this paper, we present a wideband on-chip K-band RF front-end including a transmitter and receiver for vehicular FMCW radar applications using 0.18 µm CMOS process. To achieve wideband performance, an RC feedback circuit is applied to the input stage of amplifiers, as well as wideband passive circuits such as Marchand type baluns and Wilkinson type power dividers to the mixer LO port and transmitter output, respectively. The designed chip shows a 3-dB bandwidth of 6 GHz and 4.8 GHz for the receiver and transmitter, respectively. The receiver represents a gain of 18 dB and an inputreferred 1 dB compression point of −9 dBm at an RF frequency of 24.15 GHz and an IF frequency of 100 kHz. The transmitter shows a power gain of 8.9 dB and an output power of 6.8 dBm at a frequency of 24.15 GHz. The total chip has a size of 1500 µm × 1270 µm while consuming 71 mA with a supply voltage of 1.8 V. Further, the designed RF front-end chip has been verified by radar performance tests such as the Doppler shift and range information. The test result for range information shows good agreement with theoretical expectations.