A Fully Integrated 50–280-GHz Frequency Comb Detector for Coherent Broadband Sensing

Broadband sensing and spectroscopy in millimeter wave and subterahertz frequencies can be facilitated with CMOS coherent detectors as a low-power, low-cost solution. This article presents a fully integrated coherent detector with a broadband frequency comb as an on-chip reference signal. The receiver incorporates a frequency comb generator, which provides a broadband comb as a reference for heterodyne detection, and an NMOS field-effect transistor as the heterodyne detector. It also includes an on-chip elliptical antenna with a periodic structure that enhances its directivity up to +10 dBi without using a lens. The receiver detects any arbitrary spectrum from 50 to 280 GHz with a resolution of 2 Hz by tuning the comb spacing of the reference signal from 100 MHz to 5 GHz. The chip is implemented in a standard 65-nm-CMOS process and it consumes 34-mW dc power.