A Space-Mapping-Based Optimal EM Design of RCS Reduction for Electrically Large Targets

An efficient electromagnetic (EM) optimization technique for radar cross section (RCS) reduction is proposed to achieve stealth. At first, two optimization models, namely coarse and fine models, are constructed to describe the scattering problem. More specifically, the coarse model of shooting and bouncing ray (SBR) method provides worse accuracy results than the fine model of the method of moment (MoM). However, less computational resources are needed for the coarse model when compared with the fine model. Then the SBR method is implemented into the Hummingbird optimization algorithm to obtain the solution of the coarse model. Third, the solution of the coarse model is verified for the fine model by using the MoM. Noted that the impedance boundary condition is applied to accelerate the calculation. At last, the trust region aggressive space-mapping (TRASM) algorithm is used to find the optimal solution between the SBR and MoM methods. By building the mapping relationship between these two models, the optimization efficiency can be significantly improved with high accuracy. Numerical results are given to demonstrate that the proposed optimization technique can be used as a fast tool for the cloaking design of RCS reduction. It is found that the RCS can be reduced largely by using the proposed optimization technique.