NMOS Device Optimization for the Design of a W-Band Double-Balanced Resistive Mixer

This letter describes the implementation of NMOS devices in a passive ring mixer whose operating frequency reaches device´s cut-off frequency. Conversion gain, linearity and required LO power are discussed regarding device geometry using simple analytic formulas and electrical simulations. The mixer is then embedded in a down-converter including RF, LO and IF buffers and integrated in a 130 nm BiCMOS SiGe technology. Measurements indicate a conversion gain of 14.5 dB at 76.8 GHz, an output-referred 1 dB compression point of -10 dBm and a DSB noise figure of 6.3 dB confirming the interest of double-balanced passive mixers at millimeter-wave frequencies.