A 30–65 GHz reduced-size modulator with low LO power using sub-harmonic pumping in 90-nm CMOS technology

In this paper, a reduced-size modulator with low LO power using a novel sub-harmonic mixer is presented. Compared to a conventional sub-harmonic mixer, this mixer is pumped by differential LO signals rather than quadrature LO signals. Therefore, the numbers of baluns, couplers, and mixing transistors used in this design are less than the ones used in a conventional modulator. The required LO power is also lower. This modulator demonstrates a measured conversion gain of -8 ~ -13.5 dB when RF frequency varies from 30 to 65 GHz with 4-dBm LO power. The chip size is 890 × 560 μm² including pads.