This paper presents a low-IF sampling mixer topology based on a new pulse shaper and designed for automotive radar application. The sampling mixer operation principle is described. Then an original pulse shaper topology convenient for a 77 GHz sampling operation is proposed and implemented in 28-nm FD-SOI CMOS technology. Measurement results show a 1dB input-referred compression power (ICP1dB) of +6.7 dBm and a 9.1 dB Noise Figure (NF) with a conversion gain of-0.7 dB. The power consumption of the mixer is 10 mW on a 1V supply.