Electromechanical-Thermal Coupling Modeling of Scattering Fields for Conformal Load-Bearing Antennas

During service, conformal load-bearing antennas (CLBAs) are subjected to the coupled effects of aerodynamic and aerothermal loads. The resulting geometric distortion of the array surface, deflection of element pointing, and temperature drift of the material electromagnetic parameters lead to the degradation of radar cross-section (RCS) characteristics. To overcome the limitation of existing scattering models in uniformly describing the aforementioned multi-physics coupling effects, this paper proposes a comprehensive electromechanical-thermal coupled modeling method for the scattering field of CLBAs. This method establishes a complete mapping from flight conditions to the array RCS by incorporating geometric corrections for element-level pointing deflection and bending deformation, material corrections accounting for the temperature-dependent antenna efficiency, and phase corrections induced by aerodynamic displacements. Verification using a 9 × 9 cylindrical conformal array shows that, within a scanning range of ±30°, the model calculations agree with HFSS full-wave simulations with an absolute error of less than 1 dB, and the broadside RCS is reduced by 14.97 dB compared with that of a planar array. Furthermore, a BP neural network surrogate model is constructed to achieve accurate prediction of the array physical fields. Analyses across the Mach regime of 0.20-0.65 Ma indicate that structural deformation is the dominant cause of RCS distortion, with the trailing-edge array experiencing a rapid nonlinear increase in RCS peak increment, reaching up to 7 dB at 0.65 Ma. The proposed model provides an effective theoretical tool for the rapid evaluation of stealth performance for conformal antennas operating in complex environments.