A 15/30/60-GHz 1TX/4RX Radar Chipset Achieving 6° Angular Resolution Using Frequency Dimension for Virtual Aperture Expansion

The angular resolution of a millimeter-wave FMCW radar can be significantly improved by stimulating antenna arrays with multiple frequencies, thus diversifying electrical distances under a fixed physical distance across antenna elements to expand the virtual aperture. With three different stimulating frequencies, the radar array that includes N transmitters and N receivers can form a virtual array of N6 elements in addition to MIMO operation, which creates only N2 virtual elements. As a proof-of-concept, we demonstrate a single-channel TX chip and a dual-channel RX chip in 65-nm CMOS technology. The chips can operate at 15, 30, and 60 GHz with >23% bandwidth. In the system demonstration, we use 1 TX chip and 2 RX chips to form a 1 TX and 4 RX demonstration board. The over-the-air (OTA) demonstration shows a 6° angular resolution, which is improved by 4× compared to the conventional 1 TX and 4 RX radar system.