High Frequency Asymptotical Method Based On Beam Tracing And Its Applications

High frequency asymptotic method (HFAM) is one of the most important algorithms in the area of computational electromagnetics, which has important impacts and values in electromagnetic engineering. In this dissertation, we have further investigated on the shooting and bouncing ray (SBR) algorithm, which is the most important in HFAM and focused on the improving algorithm based on tube tracing techniques, and applications in several engineering problems. The main contributions of this dissertation include:1. We introduce the fundamental principle and realization of SBR based on ray tracing (RT-SBR), including the ray tracing algorithm (RT), the geometry optics theory (GO) and the physical optics theory (PO). Then an improvement algorithm— SBR based on beam tracing (BT-SBR) is proposed. We not only detail every part of the beam tracing algorithm (BT) but also make a comparison with the traditional RT-SBR. According to such comparison, we prove from the theoretical aspect that BT-SBR is more accurate and faster than RT-SBR. Several numerical examples are also provided to validate the conclusion.2. We make great efforts on the application of BT-SBR in engineering, including the reduction of radar cross section (RCS) of complicated targets and the Inverse Synthetic Aperture Radar (ISAR) imaging of target in complex environments. Then two improvements of BT-SBR are proposed. The dielectric BT-SBR technique is applied to solve problems in the through wall radar image sensing while the BT-SBR based on pattern excitation is utilized to make the integrated simulation of antenna/antenna array and its platform. After the explanation of these electromagnetic models, we also introduce several numerical examples in these problems to display the accuracy of BT-SBR.In conclusion, our discussions are focused on the advantages of beam tracing and reviews on the problems encountered. We also give suggestions for further developments of the BT-SBR algorithm.