A novel 30-to-160GHz coherent detector is demonstrated in 65nm CMOS that uses an on-chip frequency comb as its reference. The frequency comb is locked to an external sub-The tunable comb is used as a frequency ruler to downconvert mm-wave frequency tones to intermediate frequencies between 10 MHz and 1.9 GHz. A heterodyne FET detector mixes the received signal with the on-chip frequency comb. An on-chip elliptical antenna with a metasurface bottom layer receives the radiated signal and feeds it to the source of the heterodyne detector. This chip consumes 34 mW from a 1.2V power supply.
Measurement results show a 2-Hz line width on the detected tones, which sets the minimum detection resolution. This detector can coherently detect any frequency tone from 30 to 160 GHz with a resolution that is only limited to the line width while consuming a low power consumption. Therefore, this chip can be utilized in high-resolution mm-wave sensing and spectroscopy applications. Integrated systems based on the presented comb generation and heterodyne detection techniques demonstrate strong potential in developing broadband coherent detectors in the mm-wave/THz regime.