CMOS based mm-Wave Phase Shifter for Automotive Radar Beam-Steering Applications

Abstract

In the past decade, much of research has gone into road safety concerns due to the fact that the deaths from accidents has been increasing with each passing year. This has led to a standardized system referred to as Advanced Driver Assistance System (ADAS). The ADAS is composed of a number of sensor system augmenting the driver for safer drive. In ADAS, the potential of automotive Long-Range-Radar (LRR) can be enhanced, which lacks catering a few scenarios faced by vehicles. Scenarios, like, aligning boresight of the LRR and head-on of the vehicle moving through bends and curved roads and radiation reflection clutter due other vehicles also deployed with LRR. By beamsteering of the radar radiation, the much of the challenges can be mitigated and potential of LRR can be enhanced. By using phase shifters to steer the beam in the desired direction as implemented in AESA radar systems. This also exponentially reduces resource usage and provides better control over beam direction. A novel phase shifting technique is presented, which addresses the phase shifting challenges of mm wave frequency, termed as Vector-Bisecting phase shifter. Design of phase shifter circuit has been demonstrated, of 8-bit (1.40625° step size) phase resolution, with negligible RMS phase and gain error at schematic level. By incorporating process variations for each stage the RMS phase error and RMS gain error resulted in 0.9082° and 0.7201 dB, respectively. One-time calibration transistors are included to lower RMS errors after fabrication.