A 3 - 5 GHz UWB radar chip for surveillance and reconnaissance applications is fabricated in 0.13um CMOS process. The UWB radar chip employs the equivalent time sampling and 4-channel time interleaved sampler architecture. The DC offset calibrator and BJT based circuit greatly reduce the DC offset issues. The analog signal processing part employs the proposed high speed track and hold (T/H) circuit. The direct loop back test shows the feasibility of the distance sensing with 3 cm resolution at the several meter distance. The chip size is 4 mm x 2.5 mm, and 81 mA / 38mA (Rx/Tx) are consumed at 1.5 V supply.