A 28-nm-CMOS Based 145-GHz FMCW Radar: System, Circuits, and Characterization

• Published in: IEEE journal of solid-state circuits Vol. 56; no. 7; pp. 1975 - 1993
• Main Authors: Visweswaran, Akshay, Vaesen, Kristof, Glassee, Miguel, Kankuppe, Anirudh, Sinha, Siddhartha, Desset, Claude, Gielen, Thomas, Bourdoux, Andre, Wambacq, Piet
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.07.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Bandwidth; Broadband antennas; Chirp; Circuit design; CMOS; Continuous radiation; D-band (110–170 GHz); Dipole antennas; frequency modulated continuous wave (FMCW); gesture recognition; Intermediate frequencies; leakage neutralization; link budget; Multiplication; Noise levels; on-chip antennas; Radar; Radar antennas; Radar detection; Radio frequency; Transceivers
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2020.3041153

This article presents frequency-modulated-continuous-wave (FMCW) radars developed for the detection of vital signs and gestures using two generations of 145-GHz transceivers (TRXs) integrated in 28-nm bulk CMOS. The performance and limitations of high-frequency radars are quantified with a system-level study, and the design and performance of individual circuit blocks are presented in detail. A 145-GHz center frequency and radar operation over an RF bandwidth of 10 GHz yield a displacement responsivity of 2<inline-formula> <tex-math notation="LaTeX">\pi </tex-math></inline-formula> rad/mm and a windowed range resolution of 30 mm, respectively. Radar operation over a 0.1-7 m range is enabled by an effective-isotropic radiated power of 11.5 dBm and a noise figure of 8 dB. The ICs feature frequency multiplication by 9 in the transmit and receive paths, sub-arrayed dipole antennas, and neutralization of TX-RX leakage via delay control. A single TRX dissipates 500 mW from a 0.9-/1.8-V drive. The use of fast chirps (5-30-<inline-formula> <tex-math notation="LaTeX">\mu \text{s} </tex-math></inline-formula>) mitigates the effect of 1/<inline-formula> <tex-math notation="LaTeX">f </tex-math></inline-formula>-noise at the intermediate frequency (IF). Extensive characterization results showcase state-of-the-art performance of the TRXs, while the code-domain multiple-input and multiple-output (MIMO) radars (<inline-formula> <tex-math notation="LaTeX">1 \times 4 </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">4 \times 4 </tex-math></inline-formula>) built with them demonstrate vital-sign and gesture detections.