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High-frequency incremental methods for electromagnetic complex source points.

机译：电磁复杂源点的高频增量方法。

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摘要

This dissertation advances knowledge in field-based High-Frequency (HF) incremental methods for electromagnetic Complex Source Points (CSP), and its most immediate impact is a significantly faster analysis and design of reflector antennas.;HF incremental methods overcome many difficulties encountered in other ray-tracing techniques, mostly when crossing shadow boundaries in the electromagnetic (EM) field predictions. The combination of HF methods with CSPs allows to speed up EM computations. CSPs are obtained by locating real electric or magnetic dipole sources in complex space. EM field patterns are derived through analytical continuation of the geometrical quantities associated with the source position; the continuation provides an exact Maxwellian description of a Gaussian Beam. When CSPs are used as basis functions, they can represent any radiated field pattern. Then, by truncating negligible beams in the direction of observation, computations are sped up compared to a plane- or spherical-wave based expansion. Because of these facts, CSPs can be used with Physical Optics (PO) based HF methods for the efficient analysis of electrically large reflectors. However, PO does not always provide accurate field predictions, especially in regions of greatest shadowing or at grazing incidence.;Therefore, I developed a HF Incremental Fringe Formulation (IFF) for CSPs to provide a correction term for PO that, when added to the total PO field, recovers an accurate estimate of the scattered field at the first asymptotic order. In addition, since PO does not have caustic problems, the new fringe asymptotic recovery is free of caustics for any geometrical configuration, too. Moreover, I also introduced a double diffraction formulation for CSPs, using the Incremental Theory of Diffraction, yielding simulation results very close to those obtained with a Method of Moments (MoM) approach.;Unlike ray-based methods, no tracing in complex space is necessary, and no caustics are generated, at the expense of an integration along the shadow boundary lines of the scatterer. Numerical comparisons between this IFF with Double Diffraction mechanisms, PO, and the MoM are provided. Results are compared for simple geometries as well as for more practical cases of reflectors illuminated by horn antennas.
机译：这篇论文为电磁复数源点（CSP）的基于现场的高频（HF）增量方法提供了知识，其最直接的影响是反射器天线的分析和设计明显更快。其他射线追踪技术，主要是在电磁（EM）场预测中跨越阴影边界时。 HF方法与CSP的组合可加快EM计算速度。通过在复杂的空间中放置真实的电或磁偶极子源，可以获得CSP。 EM场模式是通过分析与源位置相关的几何量的连续性得出的。延续提供了高斯光束的精确麦克斯韦描述。当CSP用作基本函数时，它们可以表示任何辐射场方向图。然后，通过沿观察方向截断可忽略的光束，与基于平面波或球面波的展开相比，可以加快计算速度。由于这些事实，CSP可以与基于物理光学（PO）的HF方法一起使用，以有效分析大型电反射镜。但是，PO并不总是能够提供准确的场预测，尤其是在阴影最大或掠入射率最高的区域中。因此，我开发了CSP的HF增量条纹公式（IFF）以提供PO的校正项，将其添加到总PO场，以第一个渐近阶数恢复散射场的准确估计。另外，由于PO不存在苛性问题，因此对于任何几何构型，新的条纹渐近恢复也都没有苛性。此外，我还使用增量衍射理论介绍了CSP的双衍射公式，得出的模拟结果与通过矩量法（MoM）方法获得的结果非常接近。与基于射线的方法不同，在复杂空间中没有跟踪这是必需的，并且不会产生焦散，以沿散射体的阴影边界线的积分为代价。提供了具有双衍射机制的IFF，PO和MoM之间的数值比较。比较了简单几何形状以及更实际情况下由喇叭天线照射的反射器的结果。

著录项

  • 作者

    Canta, Stefano Mihai.;

  • 作者单位

    University of Illinois at Chicago.;

  • 授予单位 University of Illinois at Chicago.;
  • 学科 Engineering Electronics and Electrical.;Physics Optics.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 180 p.
  • 总页数 180
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 遥感技术;
  • 关键词

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