Dissertation > Excellent graduate degree dissertation topics show

Application of Wavelet and Multiresolution Time Domain (MRTD) on Electromagnetic Scattering

Author: DaiShaoYu
Tutor: WuZhenSen
School: Xi'an University of Electronic Science and Technology
Course: Radio Physics
Keywords: Electromagnetic scattering Numerical Methods Wavelet MoM method Random rough surface Composite scattering Time domain multiple
CLC: TN011
Type: PhD thesis
Year: 2008
Downloads: 432
Quote: 4
Read: Download Dissertation


This dissertation is concerned with the improved algorithm of wavelet functions in the scattering problems—Wavelet MoM fast algorithm and Multiresolution Time Domain (MRTD), whose basis principle is the wavelet-Galerkin time domain (WGTD). They are developed based on the MoM and FDTD method. The conception of scaling function and mother wavelet function are presented after Multiresolution Analysis (MRA) of wavelet function, and illustrate the decomposition and reconstruction of Mallat and explicate the principle of MRA by use of Haar wavelet.To avoid the integration of wavelet functions, the discrete wavelet MoM method is used in the paper, that is, impendence matrix approximation at high level is calculated using MoM method, which was obtained with pulse base and dirac-δtesting. We use Daubechies’wavelet of order 6 and Coifleit wavelet of order 4 to sparsify matrix upon transforming it into the standard matrix through FWT. After the sparse matrix is created by setting threshold, the row-indexed sparse storage technique is used to accelerate multiplying operations matrix with vector in Bi-CGSTAB iterative solver. Scattering of electromagnetic waves from a two-dimensional groove in an infinite conducting plane is studied numerically using the hybrid method of PO and wavelet MoM. At last, we compute the scattering and composition scattering of random rough surface using wavelet MoM method, and the results show the advantages of computational efficiency of this algorithm.FDTD is a powerful numerical technique in electromagnetic field computation; however to restrain its numerical dispersion, fineness cells are required, which takes more computer resources and longer computing time. To circumvent this, we make a professional research on MRTD based Daubechies’scaling function with two vanishing moment. An interface between FDTD and MRTD method is presented and MRTD method is successfully applied in the EM scattering problems. MRTD method can enlarged cells size to reduce memory without sacrifice accuracy, so it has better computational efficiency. Compared with FDTD, MRTD has less phase error and so its numerical dispersion is less with the same cells size. It is well known that the effect between circumstance and object is very complicated but has an important role in EM scattering. The EM scattering of target, which is in lossy half space, is computed by MRTD method. We construct the fractal model of clustered particles and then analysis its scattering characteristic using MRTD method. Through parameter setting, plasma is equivalent to Debye dispersive media. The Auxiliary Differential Equations (ADEs) is a flexible method in dispersive media for FDTD method, we combine its procedure with MRTD method and compute the scattering of Debye dispersive media and plasma correctly. The validity and accuracy of MRTD method for dispersive media are proved through obtained results.

Related Dissertations

  1. The Analysis of Additional Stress and Displacement Fields in Layered Rock Mass Induced by Reservoir Impounding,TV223.1
  2. Research on the Algorithm of Curve RWG Basis Function Applied to Adaptively Modified Characteristic Basis Function Method,O441.4
  3. Study on Optical Heterodyne Detection for Synthetic Aperture Ladar,TN958
  4. Random rough surface light scattering characteristics of,TN011
  5. Study on Swept-Frequency Measurement of Complex Permittivity Based on Microwave Dielectric,TM934.3
  6. Radar Image Simulation of Complex Targets,TN955.2
  7. The Research on Numerical Methods of Electromagnetic Scattering from Rough Surfaces,TN011
  8. Research on Numerical Methods Based on PSO,O241
  9. Application of Generalized Perfectly Matched Layer in Two-dimensional Electromagnetic Scattering Problems,O441.4
  10. Study on Electromagnetic Scattering Characteristics of Multiple Composite Conducting and Dielectric Objects,O441.4
  11. Research on Electromagnetic Scattering Characteristics of Slits,O441.4
  12. Research of Modeling and Numerical Method for Dynamics of Flexible Multibody Systems,O313.7
  13. Debye Series Expansion of Plane Wave Scattering by Homogeneous Spheroidal Particles,O451
  14. The Violation Correction Null Space Method of Dynamical Equation of Flexible Multi-body Systems,O313.7
  15. Research on Inverse Calculation of the Characteristic of the Midcourse Missile Object Based on RCS Series,TJ760.1
  16. Research on Simulation Method of Gear Transmission System Fault,TH165.3
  17. Application and Study on the Safety Appaisal of the Mine Ventilation Sistem,TD724
  18. Pricing Model Study and Empirical Analysis of China’s Convertible Bonds,F832.5
  19. The Application of the Physical Optics Method in EM Scattering from Conductor and Coating Target,TN011
  20. Investigation on Electromagnetic Scattering of Vegetation Model on Rough Ground Surface,TN011
  21. FDTD Technique Analysis on the Scattering of Targets Coated with Plasma,TN011

CLC: > Industrial Technology > Radio electronics, telecommunications technology > General issues > Basic theory > Radio wave propagation,the propagation mechanism
© 2012 www.DissertationTopic.Net  Mobile