A 200-to-257GHz Autodyne FMCW Phased-Array Radar with 2D Beam-Steering in 55nm BiCMOS

This paper presents a 4×4 sub-THz autodyne FMCW phased-array radar with a center frequency of 228GHz and a wide tuning range of 57.4GHz. The radar unit cell integrates all transmitter, receiver, and antenna components in a compact area using multifunctional blocks, ensuring no radiation grating lobes and enabling continuous 2D beam steering. Injection locking between radar unit cells is achieved through compact edge and cross-coupling networks, establishing the necessary boundary conditions for the desired operational modes. An optimized hypo-hemispherical lens-integrated design provides broadband on-chip antennas that are free from beam tilting issues caused by deviations of the antennas from the lens center. Measurement results demonstrate continuous beam steering in both the E- and H-planes, with range resolution and accuracy of 2.7mm and 38µm, respectively, making it suitable for precise and rapid imaging. This work marks the first demonstration of a broadband, fully integrated FMCW phased-array radar in the sub-THz/THz domain.