基于离散伴随方程的三维雷达散射截面几何敏感度计算

A Radar Cross Section (RCS) gradient calculation method based on adjoint equation of Maxwell integral equation is proposed. This method aims to overcome the high cost and low efficiency in the traditional finite difference calculation method. The adjoint method can obtain the gradients of all design variables by one radar cross-section solution and one adjoint solution. The required calculation amount of the gradient solution is basically independent of the number of design variables. The form of adjoint equation is similar to the original equation, and can be solved by the Method of Moment (MOM) and Multilevel Fast Multipole Algorithm (MLFMA). The calculation and storage amount in solving adjoint equation is basically the same as the calculation of RCS. By adopting the double ogive model and a missile model, two test cases are adopted to ve-rify the reliability and precision of the adjoint method. Gradients calculated based on the adjoint method of MOM and MLFMA are compared with the finite difference results. Numerical results prove the accuracy of the adjoint method, and demonstrate that it can be applied in complex shapes, providing a basis for the construction of gradient-based aerodynamics-stealth optimization framework.