4.7 A Single-Antenna W-Band FMCW Radar Front-End Utilizing Adaptive Leakage Cancellation
Milad Kalantari, Hossein Shirinabadi, Ali Fotowat-Ahmadi, C. Patrick Yue
Abstract
Millimeter-wave radars are essential for automotive sensing, medical imaging, and safety- monitoring applications. Among different architectures, frequency-modulated continuous-wave (FMCW) radars are particularly suited for miniature integration targeting portable consumer applications with detection ranges up to a few tens of meters. This translates to a relatively low requirement of transmitter (TX) output peak power and hence is well suited for implementation using low-supply-voltage CMOS processes. To avoid saturating the receiver (RX) under CW operation, FMCW radars must achieve high TX-to-RX isolation in the front-end. Typically, at least 40dB of isolation is necessary for W-band (75 to 85GHz) FMCW radars, which usually employ separate TX and RX antennas. Hence, this requirement dictates the minimum achievable radar size as a typical W-band planar antenna array requires a footprint of about 10cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Sharing a single antenna between RX and TX is thus highly desirable to reduce the overall form factor, which is paramount for portable systems. As a result, different analog and digital TX leakage-cancellation circuit techniques have been proposed to support single-antenna operation [1], [2]. In this work, we present a single-antenna TRX SoC and module design for an 80GHz FMCW radar featuring continuous-time adaptive leakage cancellation.