一种用于76-81 GHz汽车雷达的CMOS毫米波下混频器

A CMOS millimetre wave down-conversion mixer for 76-81 GHz automotive radars

设计了一款用于76~81 GHz汽车雷达的CMOS毫米波正交下混频器,该混频器由前置放大、有源正交混频两部分构成。在前置放大器中,采用基于变压器的跨导增强技术改善了增益。在有源正交下混频器中,使用并联电感谐振结合交叉耦合管动态电流注入技术,消除跨导管与开关管之间的寄生电容,降低混频器噪声、提高转换增益。芯片采用55-nm CMOS工艺制造,测试结果表明,该下混频器3dB带宽为5.5 GHz,峰值转换增益4.1 dB,I/Q两路增益失配小于0.16 dB(50Ω负载条件),最小噪声系数19 dB,输入1dB压缩点-6 dBm,直流功耗40 mW,实现了优异的FOM值。

This paper presents a 76~81 GHz CMOS millimeter wave quadrature down-mixer for automotive radars.The transformer-based gm-boosted method is utilized in the pre-amplifier for improving gain performance.A parallel inductor and two cross-coupled transistors with dynamic current-bleeding are combinatorially exploited to resonate the parasitic capacitance between the transconductance stage and the switching stage and improve noise figure and conversion gain.The proposed mmW down-mixer is implemented in a 55-nm CMOS process and the measurement results show that the BW-3dB is 5.5 GHz,the peak gain is up to 4.1 dB with<0.16 dB I/Q mismatch(at 50Ωload),the input P1dB is-6 dBm and the minimum noise figure is of 19 dB while consuming 40 mW of power.Excellent FOM is achieved by combining above-mentioned techniques.