A Simple Combined-Field Integral Equation Strategy for Electromagnetic Scattering from PEC Objects

The combined-field integral equation (CFIE) usually is less accurate than the electric-field integral equation (EFIE), especially for objects with sharp edges and corners. In this work, we propose a simple but accuracy enhanced CFIE (AE-CFIE) strategy for computing scattering from perfect electric conductor (PEC) objects. AE-CFIE directly replaces the original CFIE on the sharp edges with EFIE. Using the dihedral angle of the meshes to describe the sharpness of the geometric structure, the hybrid criterion of EFIE/CFIE has been studied in detail. This strategy can be implemented conveniently under exiting basis functions and only a few lines of code need to be changed. Due to the inclusion of EFIE, AE-CFIE may sacrifice the convergence speed compared with CFIE. Therefore, we also investigate the performance of AE-CFIE with or without the preconditioner. Numerical examples show the performance of AE-CFIE, and a comprehensively study is made to demonstrate its validity, reliability, and stability.