Multibeam Phased Arrays with Spherical-Gold Spatio-temporal Coding for Fading-Resilient and Delay-Robust Beam Isolations

Next generation joint communication and sensing systems require simultaneous multibeam operation with low latency hardware and robust isolation under synchronization error and fading. Conventional code division multiplexing using Walsh-Hadamard codes is extremely time sensitive. This paper demonstrates that conventional temporal only coded multibeam arrays, results in inter beam sidelobe level (SLL) collapsing to within a few dB of the main lobe and varying by more than 10–20 dB over delay. By embedding moderate length Gold sequences into a spherical spatial codebook, the proposed Spherical-Gold scheme leverages both 1/√(N ) temporal and 1/√M spatial bounds, achieving effectively 1/(√N.√M) correlation without increasing RF complexity. The measurement results and verifications have been performed using Analog Device, ADAR3002, Ka band 256 element receiver with four simultaneous beams demonstrate ≥15 dB rejection with <±2.5 dB variation of SLL under time-error and fading, while temporal only CDMA degrades toward -5 dB SLL and 16 dB variations