A low-power and wideband two-stage millimeter-wave CMOS low-noise amplifier (LNA) for 76~77 GHz long-range and 77~81 GHz short range automotive radar system is reported. T-match technique is utilized to achieve simultaneously wideband input and output impedance matching, wideband power gain (S2i) and wideband noise figure (NF). The LNA consumes 7.2 mW, achieving S11 better than -10 dB for frequencies of 74.3~104.4 GHz, and S12 better than -21.4 dB for frequencies of 10~110 GHz. The corresponding input matching bandwidth is 30.1 GHz. Additionally, high and flat S21 of 17.3±1.5 dB is achieved for frequencies of 74.1~82.4 GHz, which means the corresponding 3-dB bandwidth is 8.3 GHz. Furthermore, the LNA achieves minimum NF of 7.4 dB at 81 GHz and excellent FOM of 1.88 GHz/mW. To the authors' knowledge, the achieved FOM is one of the best results ever reported for a CMOS or SiGe BiCMOS LNA with operation frequency around 77 GHz.