A Fully Integrated Coherent 50–500-GHz Frequency Comb Receiver for Broadband Sensing and Imaging Applications

This paper presents a fully integrated oscillator-less frequency-comb receiver for broadband sensing, spectroscopy, and imaging in millimeter-wave and THz bands. The chip consists of a THz pulse generator block to generate the reference tones for coherent frequency comb detection. The repetition rate of the reference pulses (LO frequency comb) are tunable over a 4-10.5 GHz range, with the highest sensitivity achieved at 9 GHz. A broadband on-chip antenna with a peak directivity of 15 dBi is employed for broadband detection. The receiver, which is capable of detecting any arbitrary spectrum, is characterized from 140 GHz to 500 GHz using continuous-wave sources. Peak sensitivity of -105 dBm is achieved at 261 GHz. The chip is implemented in 130-nm SiGe BiCMOS technology and consumes only 52-mW DC power. The chip can also be used as a frequency comb radiator. Chip-to-chip dual-comb measurement is performed using two identical chips in the radiator and receiver modes, respectively up to 450 GHz.