A 210 GHz Dual-Gate FET Mixer MMIC With ${>}$ 2 dB Conversion Gain, High LO-to-RF Isolation, and Low LO-Drive Requirements

We demonstrate the first active mixer monolithic microwave integrated circuit (MMIC) with positive conversion gain beyond 200 GHz. The presented dual-gate topology is realized in a 100 nm gate length metamorphic high electron mobility transistor technology. Without any pre- or post-amplification, the down-conversion mixer achieves > 2 dB conversion gain and > 16 dB local oscillation to radio frequency (LO-to-RF) isolation at 210 GHz, outperforming state-of-the-art resistive MMIC mixers. The conversion gain becomes positive for LO power levels larger than 0 dBm, making the mixer suitable for being driven by an MMIC-based frequency doubler. A comparison to state-of-the-art G-band mixers is given.