An Evaluated PMCHWT Solution of EM Scattering for Mutimedium Targets With Variant Permittivities

An evaluated Poggio–Miller–Chang–Harrington–Wu–Tsai (PMCHWT) is formulated in terms of the asymptotic waveform evaluation (AWE) technique to predict the scattering characteristics of multimedium targets. At first the uncertain dielectric constant can vary within a certain range by setting it as the permittivity variable. Then the evaluated PMCHWT is constructed with these permittivity variables. Noted that the inversion of the impedance matrix is needed only once and the moment matching technique is used in the process of recursion. Moreover, the high-order derivatives are applied in order to obtain the greater convergence radius. Finally, the impedance matrix, right vector, and the current density are expanded with the Taylor series. The current density is approximated by the reduced order rational Padé function. Compared with the traditional perturbation method, greater radius of convergence can be obtained by using the proposed method. In addition, higher efficiency can be obtained than the general Monte Carlo method.