关键词: 电磁伴随方程, 表面灵敏度, 雷达散射截面, 自动微分

Abstract:

The development of anti-stealth technology poses a strong challenge to the stealth performance of military aircraft. The classical electromagnetic adjoint approach cannot obtain the surface sensitivity information， and therefore cannot provide intuitive guidance for the optimal design. Moreover， in the classical adjoint approach， the need to repeatedly fill the impedance matrix during gradient calculation leads to low efficiency， particularly with a large number of design variables and incident angles. This paper proposes an approach to calculating radar cross section surface sensitivity based on the adjoint and automatic differentiation method. A sparse matrix storage method considering the characters of the Rao-Wilton-Glisson basis function is adopted to reduce the memory requirements of the impedance matrix differentiation. The proposed method can obtain the surface sensitivity of all surface nodes with one matrix differentiation calculation. For different incident angles， the calculation of design variable gradients of any number will not exceed 16 matrix-vector products. The proposed surface sensitivity calculation approach can effectively improve the efficiency of gradient calculation， and provides support to the optimal design of stealth military aircraft.

Key words: electromagnetic adjoint equation, surface sensitivity, radar cross section, automatic differentiation