A 76–81 GHz CMOS down-conversion mixer for automotive radar

This paper demonstrates a 76-81 GHz down-conversion mixer applied in automotive radar, which is characterized with high linearity, low local oscillator (LO) drive level as well as high conversion gain (CG) using TSMC 65-nm CMOS general-purpose (GP) technology. In order to satisfy both linearity and isolation requirements for an automotive radar operating in short-middle-far, the mixer proposed in this study comprises of an enhanced double-balanced Gilbert-cell core with a series peaking transmission line and source degeneration technique for improving linearity and CG, two on-chip baluns and intermediate frequency (IF) buffer for IF test. The mixer consumes 12mW under 1.5V. The input 1dB compression point (P1dB) is 2.5 d Bill as well as IIP3 of 13.2 dBm at 80 GHz. High performances are achieved with the CG of 5 dB (76 GHz) with LO power of 0 dBm for frequencies of 75-90 GHz which covers the application of automotive radar frequency band (76-81 GHz) and isolation of LO-RF of 33-37 dB for frequency range of 60-90 GHz. The area of the mixer is 0.14mm
²
, with PADs included.