Time-domain Integral Equation Method For Three-dimensional Electromagnetic Scattering

Because of the increasing interest in short-pulse radar design for high-resolutionand target identification problems, time domain integral equation (TDIE)-basedsolvers are poised to be increasingly applied throughout the computationalelectromagnetic community to the analysis of complex wide-band electromagneticscattering phenomena . In this dissertation, time domain integral equation method isstudied for transient electromagnetic scattering by arbitrarily three dimensionalconducting bodies.In the first, the time-domain electric field integral equation (EFIE), magneticfield integral equation (MFIE), and combined field integral equation (CFIE)formulations are described in detail. The general implementation of time-domainintegral equation solver is presented. The details that relate to the method of momentsused to solve the TDIE are discussed. Furthermore, two numerical algorithms to solvethe linear system are introduced.Next, after briefly discussing several causes of the late-time instability of theTDIE solvers, a novel viewpoint about the instability is proposed. Themarching-on-in-time algorithm (MOT) is described and some temporal bases arediscussed. Due to the importance of the accuracy of the time-domain impedancematrix elements, the techniques by which treating of the singular integrals arose fromthe TDIE-MOM solving process are analyzed in detail, and these techniques areutilized to solve the TDIE. Using triangle patches discretizing an arbitrarily 3-DPEC body surface and utilizing spatial RWG and temporal triangular bases, theTD-MFIE, EFIE, and CFIE are solved by MOT algorithm. Several numerical resultsshow that the proposed method is stable and accurate, and the proposed method isnearly not sensitive to the high-, low-frequency component of the incidence wave andisn't sensitive to these internal resonance modes.The dissertation also investigates the higher-order algorithm to solve TDIE. Anddetailed discussion about two aspects of higher-order method: the higher-ordergeometrical modeling and higher-order basis functions are presented. Thehigher-order TDIE algorithm for analysis of electromagnetic scattering phenomenafrom 3-D PEC bodies is founded by utilizing curvilinear triangular patches andhigher-order divergence conforming interpolatory vector basis functions. The singularintegrals are also considered. Numerical results demonstrate that the higher-order...