4.8 A Terahertz FMCW Comb Radar in 65nm CMOS with 100GHz Bandwidth

Abstract

The increasing demands for low-cost, compact, and high-resolution radar systems have driven the operation frequency to terahertz (THz) due to the shorter wavelength and larger bandwidth [1]-[5]. However, conventional single-transceiver FMCW radar chips only provide limited signal bandwidth (<; 70GHz [1]-[5]), especially when implemented using CMOS technologies with low fT and fmax. Therefore, prior THz integrated radars are based on compound semiconductors [2]-[4] and have severely degraded performance near the band edges. That not only limits their applications in high-accuracy scenarios like industrial robotics and small-defect detections, but also poses tradeoffs between bandwidth and detection range. To break such limitations, this paper adopts a frequency-comb-based scalable architecture using a paralleled transceiver array to cover an ultra-broad bandwidth. Implemented in a 65nm bulk CMOS process, a five-transceiver radar chip is prototyped with seamless coverage of the entire 220-to-320GHz band and a ranging resolution of 1.5mm. Across the state-of-the-art total chirp bandwidth of 100GHz, the output power fluctuates by only 8.8dB.