Low power and high linearity millimeter wave differential mixer using passive transformer

A low power and high linearity millimeter wave mixer for automotive radar application is designed using SiGe BiCMOS technology. The concept of design is based on a Gilbert type cell. The proposed topology uses separated voltage sources (1.5 V and 2 V for the transconductance and switching stage respectively) via a transformer. This mixer allows high output dynamic range with low power consumption. The chip was characterized by on-wafer measurements. At 77 GHz, the voltage conversion gain (G_C) and double side band noise figure (NF_DSB) are 13.7 dB and 11.4 dB respectively. Input referred 1-dB compression point (ICP_1dB) is 2 dBm. Total power consumption is 15 mW. The size of mixer core is 550 × 410 μm².