A K} -Band CMOS FMCW Radar Transceiver for Snowpack Remote Sensing

• Published in: IEEE transactions on microwave theory and techniques Vol. 66; no. 5; pp. 2480 - 2494
• Main Authors: Kim, Yanghyo, Reck, Theodore J., Alonso-delPino, Maria, Painter, Thomas H., Marshall, Hans-Peter, Bair, Edward H., Dozier, Jeff, Chattopadhyay, Goutam, Liou, Kuo-Nan, Chang, Mau-Chung Frank, Tang, Adrian
• Format: Journal Article
• Language: English
• Published: IEEE 01-05-2018
• Subjects: Absorption; Bandwidth; Chirp; CMOS; frequency-modulated continuous-wave (FMCW); phase-locked loop (PLL); Radar; range correlation; ring oscillator; Signal to noise ratio; Snow; snow depth measurement; Spatial resolution
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2018.2799866

This paper presents a <inline-formula> <tex-math notation="LaTeX">K_{u} </tex-math></inline-formula>-band (14-16 GHz) CMOS frequency-modulated continuous-wave (FMCW) radar transceiver developed to measure dry-snow depth for water management purposes and to aid in retrieval of snow water equivalent. An on-chip direct digital frequency synthesizer and digital-to-analog converter digitally generates a chirping waveform which then drives a ring oscillator-based <inline-formula> <tex-math notation="LaTeX">K_{u} </tex-math></inline-formula>-Band phase-locked loop to provide the final <inline-formula> <tex-math notation="LaTeX">K_{u} </tex-math></inline-formula>-band FMCW signal. Employing a ring oscillator as opposed to a tuned inductor-based oscillator (LC-VCO) allows the radar to achieve wide chirp bandwidth resulting in a higher axial resolution (7.5 cm), which is needed to accurately quantify the snowpack profile. The demonstrated radar chip is fabricated in a 65-nm CMOS process. The chip consumes 252.4 mW of power under 1.1-V supply, making its payload requirements suitable for observations from a small unmanned aerial vehicle.