Design of high-linearity 75–90?GHz CMOS down-conversion mixer for automotive radar

摘要

This paper presents a 75–90?GHz down-conversion mixer applied in automotive radar, which is characterized with high linearity, low local oscillator (LO) drive as well as high conversion gain (CG) using TSMC 65-nm CMOS general-purpose technology. The good linearity and isolation of mixer are required for automotive radar to cover short-middle-far range detection. The mixer includes an enhanced double-balanced Gilbert-cell core with 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. Besides, to make the design more accurate and efficient, the modeling and design of millimeter-wave (mm-wave) passive devices are introduced. The mixer consumes 12?mW under 1.5?V. The input 1?dB compression point (P~(1dB)) is 2.5?dBm as well as IIP3 of 13.2?dBm at 80?GHz. High performances are achieved with the CG of 5?dB at 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 LO-RF isolation of 33–37?dB for frequencies of 60–90?GHz. The area of the mixer is 0.14?mm_(2), with PADs included.