An Active Double-Balanced Down-Conversion Mixer in InP/Si BiCMOS Operating from 70-110 GHz

In this paper, a double-balanced Gilbert cell down-conversion mixer is demonstrated from 70-110 GHz. The wide bandwidth and high frequency are enabled by the HRL InP/Si BiCMOS process. With an fT of 300 GHz, the available 0.25 mu m InP HBTs are used in the signal path while the 90nm CMOS devices are used for biasing and gain adjustment. The fully differential circuit is implemented using two on-chip Marchand baluns feeding both the LO and RF ports. An IF buffer follows the mixer to improve matching and signal quality for testing. After de-embedding the balun and IF buffer, the mixer core achieves a peak conversion gain of 13 dB, a minimum DSB NF of 10 dB, and an OP1dB of -2 dBm while consuming 5 mA from a 3.3 V supply.