Radar sensors have moved in the past years from bulky systems to integrated solutions, driven by the needs of many applications in varying domains. They are the key component in self-driving cars, to provide robust sensing capabilities in every weather condition. They allow to monitor vital signs such as breathing and heart rate of elderly people. One of the latest applications is gesture recognition in recent smartphones.
The key component in a modern radar is a frequency-chirping Phase-Locked Loop (PLL), that generates an ultra-clean sinewave of a linearly increasing frequency. This Frequency-Modulated Continuous Wave (FMCW) radar system allows to detect both distance and speed of targets in the environment. The transmitted signal reflects on such targets, and is received by the receiver after a certain time proportional to the propagation time (at the speed of light) to travel back and forth from the radar. The receiver mixes this signal with the same FMCW source signal, and the beat frequency at the output of this is a measure of the distance traveled.
Many of the key performance criteria of the radar system are determined by the quality of the generated FMCW source. Any nonlinearity in the frequency vs time curve will cause errors in the detected distance and speed. Any noise in the system will prevent the detections of small targets, hidden in the noise floor. The total available bandwidth that can be generated (difference between maximum and minimum frequency) determines the range resolution of the radar, several GHz of bandwidth are required for cm-accurate detection of targets.
This PhD will try to push further the performance of FMCW PLLs, combining novel mixed-signal signal processing and calibration techniques with state of the art design of the key building blocks such as Voltage-Controlled Oscillator (VCO) and Digital-to-Analog converters (DAC). Key aspects will be a reduction of power consumption for operation in battery-powered devices, and an increase in available bandwidth to enable new applications with high range resolution.
We’re looking for a highly motivated PhD student with sufficient background in analog circuit design, capable of understanding and modelling complex mixed-signal systems.