55-100-GHz Enhanced Gilbert Cell Mixer Design in 22-nm FDSOI CMOS

This article presents a wideband active millimeter wave (mmWave) CMOS downconversion mixer preceded by thorough analysis. This article aims to provide solid reasoning for the proper choice of mixer topology and present methods to achieve high mixer performance, guiding mmWave mixer design. The article first analyses passive and active mixer input impedance and switching performance with a weak sinusoidal local oscillator (LO) signal, demonstrating that passive mixer switching performance is far more dependent on the LO signal. The article then introduces different active mixer design enhancement techniques, namely, peaking inductances and individual mixer stage biasing. The article proposes an enhanced Gilbert cell mixer that uses transformer coupling between the transconductance and switching stages. The complete mixer structure with an LO buffer and an IF amplifier consumes an area of only 0.13 mm² fabricated in a 22-nm FDSOI process. The design achieves a measured peak voltage conversion gain (CG) of 3.5 dB, an exceptionally wide 55-100-GHz RF bandwidth, and a 10-GHz IF bandwidth. The complete mixer consumes 33 mW of power from a low 0.8-V supply voltage and demonstrates an input 1-dB gain compression point of -6 dBm.