A 30-100 GHz wideband sub-harmonic active mixer in 90 nm CMOS technology

This letter presents a 30-100 GHz wideband and compact fully integrated sub-harmonic Gilbert-cell mixer using 90 nm standard CMOS technology. The sub-harmonic pumped scheme with advantages of high port isolation and low local oscillation frequency operation is selected in millimeter-wave mixer design. A distributed transconductance stage and a high impedance compensation line are introduced to achieve the flatness of conversion gain over broad bandwidth. The CMOS sub-harmonic Gilbert-cell mixer exhibits -1.5 ± 1.5 dB measured conversion gain from 30 to 100 GHz with a compact chip size of 0.35 mm ². The OP_{1 dB} of the mixer is -10.4 dBm and -9.6 dBm at 77 and 94 GHz, respectively. To the best of our knowledge, the monolithic microwave integrated circuit is the first CMOS Gilbert-cell mixer operating up to 100 GHz.