A 60 GHz down-conversion mixer with 6.6 dB gain and 11 GHz IF bandwidth in an 80 GHz SiGe HBT technology

In this paper, the authors present a wide-band down-conversion mixer with 11 GHz IF bandwidth, which is especially suited for 60 GHz applications. The mixer employs a Gilbert cell mixer core and a transimpedance (TI) load to increase the IF bandwidth. For a fixed LO at 55 GHz with 0 dBm power, a flat conversion gain of 6.6 dB (± 0.4 dB) was measured over the frequency range from 56 GHz to 65 GHz, with both RF and LO driven single-endedly. 3 dB more conversion gain can be achieved when both RF and LO are driven differentially (in simulation). Emitter degeneration is used to improve the linearity and the measured input 1 dB compression point is -10 dBm. The measured LO to RF and LO to IF suppression (with LO driven single-endedly) is better than 25 dB and 37 dB. The mixer is realized using a 0.8 μm SiGe HBT technology with 80 GHz f_T and draws 17.2 mA current from a 4V supply.