The asymptotic waveform evaluation （AWE） technique is a rational function approximation method in computational mathemetics, which is used in many appllcations in computational electromagnetlca. In this paper, the performance of the AWE technique in conjunction with hybrid finite element/boundary integral （FE/BI） method is firstly Inveetlgeted. The formuletlon of the AWE applied in hybrid FE/BI method is given in detail. The characteristic implementation of the application of the AWE to the hybrid FE/BI method is discussed. Numarlcel results demonstrate that the AWE technique can greatly speed up the hybrid FE/BI method to acquire wide-band and wide-angle backecatter radar-cross-section （RCS） by complex targets.
PENG Zhen1,2,3 & SHENG XinQing2 1 Institute of Electronics, Chinese Academy of Sciences, Beijing 100080, China
A computational approach of scattering by buried objects is presented by using finite-difference time- domain （FDTD） method, the uniaxial perfectly matched layer （UPML）, and reciprocity theorem. The nu- merical performance of this approach is investigated by numerical experiments. The radar cross sections （RCS） of various buried objects with different electrical sizes, shapes, dielectric constants, are computed and ana- lyzed. The results show that for the conducting cube, the RCS curves are fluctuant, but for the sphere shape one, the curves are smooth. Comparing with scattering in the free space, the ground greatly affects the RCS by dielectric targets, but little does by conducting targets. For the buried dielectric objects, iterative steps can be evaluated by four to five round-trip traversals of the Huygens box, but for the conducting ones, the time steps can be reduced to three round-trip traversals. When the ground is lossy, the run-time can be reduced more to two round-trip traversals.
