This paper proposes a new switched-capacitor sigma-delta modulator for automotive radars. Developed modulator is used to perform high-resolution analog-to-digital conversion (ADC) of high frequency band signal in a radar system. It has supply voltage of 2.7V, and has body-effect compensated switch configuration with low voltage and low distortion. The modulator has been implemented in a $0.25{mu}m$ double-poly and triple-metal standard CMOS process, and it has die area of $1.9{ imes}1.5mm^{2}$. It showed better total harmonic distortion of 20dB than the conventional bootstrapped circuit at the supply voltage of 2.7V.