Investigation of Broadband Scattering Properties of PEC/Dielectric Composite Objects Using Adaptive Integral Methods and Asymptotic Waveform Evaluation

In this communication, we propose a novel technique based on the electric field integral equation (EFIE)-coupled Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) equation to effectively analyse the broadband properties of dielectric/metallic composite objects. In the conventional asymptotic waveform evaluation (AWE) technique, the Padé approximation solution obtained by Taylor series fitting is used to achieve a fast frequency sweep. In addition to computing and storing the high-order frequency derivatives of the impedance matrix, the moments of the linear system have to be solved iteratively. In this communication, the pseudo-spectral derivative method (PSDM) is used to derive the high-order impedance matrix at the center point from the zero-order impedance matrix at the AWE sampling point based on Gauss-Lobatto-Chebyshev (GLC) interpolation. Furthermore, the adaptive integral method (AIM) is used to solve integral equations and reduce the storage of zero-order impedance matrices. It also speeds up all matrix-vector multiplications in linear matrix systems and iterative solvers. The results of the three numerical examples show that the proposed method achieves higher computational efficiency by avoiding full frequency sweeps, while maintaining accuracy in computing wideband scattering responses.