Announced at the International Microwave Symposium (IMS, Philadelphia, USA), the chip represents an important step in the development of radar-based sensors for a myriad of smart intuitive applications, such as building security, remote health monitoring of car drivers, breathing and heart rate of patients, and gesture recognition for man-machine interaction.
If designed much smaller, cheaper and power efficient than todays' solutions, radars could enable contactless, non-intrusive interaction in many IoT applications including people detection and classification, vital signs monitoring and gesture interfacing. The chip-based low-power 140 GHz radar solution demonstrated by imec is a proprietary two antenna SISO (Single Input Single Output) radar transceiver chip and a frequency modulated continuous wave phase-locked loop (FMCW PLL), off-the shelf ADCs and FPGA and a Matlab chain.
The transceiver features on-chip antennas achieving a gain close to 3 dBi. The excellent radar link budgets are supported thanks to the transmitter Effective Isotropic Radiated Power (EIRP) exceeding 9 dBm and a receiver noise figure below 6.4 dB. The total power consumption for transmitter and receiver remains below 500 mW, which can be further reduced by duty cycling. The FMCW PLL enables fast slopes up to 500 MHz/µs over a 10 GHz bandwidth around 140 GHz with a slope linearity error below 0.5% and has a power consumption below 50 mW.
The FPGA contains real-time implementation of basic radar processing functions such as FFTs (Fast Fourier Transforms) and filters, and is complemented by a Matlab chain for detections, CFAR (Constant False Alarm Rate), direction-of-arrival estimation and other advanced radar processing.
“With our prototype radar, we have demonstrated all critical specs for radar technology in 28nm standard CMOS technology,” said Wim Van Thillo, IoT program director at imec.