A 28-GHz Bidirectional Active Gilbert-Cell Mixer in 90-nm CMOS

A bidirectional active mixer based on Gilbert-cell topology is proposed and realized in 90-nm CMOS at 28 GHz. The offered mixer can achieve both the up- and down-conversion under 1-dBm local oscillator (LO) power by adjusting the Gilbert quad switch's gate bias. An IF bidirectional amplifier (IFBDA) is adapted to compensate for the conversion loss (CL) of the Gilbert quad switch. The measured peak conversion gain (CG) is -2.14/-3.28 dB at 28-GHz, and the 3-dB bandwidth is 7/6 GHz in transmit (Tx)/receive (Rx) mode. Total dc power consumption is only 8.4/6.4 mW for Tx/Rx mode under 1.2-V supply voltage. Compared with the traditional bidirectional passive mixers, this mixer demonstrates a low CL with a low LO power.