Electromechanical thermal coupling model and performance compensation methods for slotted waveguide array antenna

Spaceborne slotted waveguide array antennas (SWAAs) face severe electromagnetic performance degradation due to harsh orbital thermal environments. This degradation stems from microscopic structural warping–which perturbs the coupled slot transimpedance matrix–and channel-level T/R module drift. To restore the distorted radiation characteristics, this paper establishes a rigorous active electromechanical-thermal coupling model (ETCM) along with a two-stage digital compensation framework. Unlike conventional arrays, slot excitations in the corporate-fed SWAA are implicitly coupled; thus, a sequential mesh-transfer procedure is developed to extract the dynamic transimpedance matrix via 3D full-wave calculation. For aperture reconfiguration, Stage I utilizes Least Squares Estimation for continuous compensation, while Stage II applies a deterministic threshold and a multi-objective genetic algorithm to simultaneously suppress the maximum sidelobe level (MSLL) and minimize beam pointing deviations. Quantitative full-wave verification under extreme thermal scenarios ( \(120∘C\) to \(-160^∘ C\) ) demonstrates exceptional alignment, with absolute tracking discrepancies of MSLL and beam pointing errors tightly bounded within 0.66 dB and \(0.01^∘\) , respectively. This paradigm successfully bridges multi-field modeling and finite-bit beam control for spaceborne radar applications.