Hybrid CFIE-EFIE solution of composite geometries with coexisting open and closed surfaces

The combined-field integral equation (CFIE) is employed to formulate the electromagnetic scattering and radiation problems of composite geometries with coexisting open and closed conducting surfaces. Conventional formulations of these problems with the electric-field integral equation (EFIE) lead to inefficient solutions due to the ill-conditioning of the matrix equations and the internal-resonance problems. The hybrid CFIE-EFIE technique introduced in this paper, based on the application of the CRE on the closed surfaces and EFIE on the open surfaces, significantly improves the efficiency of the solution.