Efficient Method Based on SMW Formula for Analyzing PEC Targets with Partial and Thin Coatings

Abstract

The analysis of the electromagnetic scattering from the perfect electric conductor (PEC) partially coated with thin material is a significant task in stealth design. Previous research has shown the scattering can be calculated by only discretizing the current on PEC in the case of thin coating layers. However, it has a downside that it will recalculate a complete solution when the geometry or electromagnetic properties of the coating changes. In this paper, a Sherman-Morrison-Woodbury (SMW) formula-based method is proposed to address this problem. According to the SMW formulation, it can reuse the inverse impedance matrix of the PEC part to efficiently obtain the solutions when local coating changes, so it can avoid the subsequent complete inverse of the new impedance matrix. Furthermore, it employs the fast direct solution method based on the SMW formulation to accelerate the calculation of inverse matrix of the PEC part. Numerical results demonstrate the performance of the proposed method.