A Multichip Ka-Band Phased Array With a Scalable Self-Aligning Architecture

We present a multichip scalable phased array based on nearest-neighbor phase self-alignment. The proposed scheme relies on mm-wave interferometric phase detection and baseband phase adjustment forming a distributed phase control scheme. We introduce the architecture and develop a proof of concept array where the chips are fabricated in the TSMC 65 nm process. We form the multichip array by implementing mm-wave chip-to-chip interconnects for phase control with an on-board antenna array. Over-the-air measured patterns produce reliable inter-element phase values resulting in calibration-free beam steering for up to 1\,\, {}\times {}7 radiating elements. The measured ±30° beam steering and steps across 27.4-32.4 GHz are consistent with predictions from simulation, demonstrating a novel distributed method to produce large-scale coherent beamforming arrays.