This paper investigates a concept for a 79 GHz millimeter-wave receiver (Rx) frontend optimized for highly linear frequency-modulated continuous-wave civil-automotive radars. It consists of a double-balanced passive ring mixer for the frequency down-conversion, and two highly-linear differential amplifiers as low-noise amplifier and driver for the local-oscillator (LO) signal. To prove the concept, the circuit is implemented in a 22nm FDSOI CMOS technology. It is also studied how the control of the threshold voltage by the back-gate (BG) biasing can increase the circuit performance. Leveraging this feature, no dc biasing is required for the passive mixer and the trade-off between gain and linearity of the amplifiers can be easily tuned with the BG voltage. To characterize the Rx, the chip is mounted on a print circuit board with external resistive loads. Measurements of the fabricated chip show a maximum differential voltage conversion gain (CG) of 10.8 dB at a 1 kO load and the minimum double side-band NF (NFdsb,min) of 9.7 dB with a 50O-load. The simulation shows that the NFdsb,min can be further improved, while the Rx drives a higher resistive load. With a 1 kO load, the simulated NFdsb,min is 7.5 dB. In the measured RF signal range from -30 dBm to -5 dBm, the CG is nearly linear, and the simulated input-referred 1dB-compression-point is between -4 dBm to -2 dBm depending on the LO frequency. To the best knowledge of the authors, this is the highest reported.