Computer Techniques for Electromagnetics

Preface1. A Brief Preview References2. Wire Antennas 2.1. Introduction 2.2. Integral Equations for Wire Antennas 2.2.1. A Volume Equivalence Theorem 2.2.2. Pocklington's Integral Equation 2.2.3. Hallen's Integral Equation 2.3. Method of Moments 2.3.1. Galerkin's Method 2.3.2. Point-matching 2.4. Bases 2.4.1. Entire-domain Bases 2.4.2. Sub-domain Bases (Segmentation) 2.4.3. Some Common Basis Functions 2.4.4. A Basis Transformation Method 2.4.5. Piecewise-sinusoidal Basis: Reaction-matching 2.4.6. Characteristic Mode Currents: An Eigenvalue Problem 2.4.7. The Stability Problem 2.5. Calculation of Antenna Characteristics 2.5.1. Current Distribution, Impedance and Lumped Loading 2.5.2. Radiation Patterns, Gain and Efficiency 2.6. The Yagi-Uda Array 2.6.1. The Integral Operator 2.6.2. Matrix Formulation 2.6.3. Far-zone Radiation 2.6.4. Current Distributions 2.6.5. Array Input Impedance 2.7. Electrically Small Antennas 2.7.1. Multiturn Loop Antenna 2.7.2. TEM-line Antenna with Loading 2.8. Modeling of Wire Antennas on Metallic Bodies 2.8.1. Monopole or Circular Slot in the Base of a Cone 2.8.2. Small Loops of TEl Line on an Aircraft 2.9. Conclusions and Acknowledgment 2.10. Exercises Appendix I. Fields of a Magnetic Frill Current Appendix II. Calculation of Characteristic Mode Currents Appendix III. Fortran IV Program for Wire Antennas on Metallic Bodies References 3. Numerical Solution of Electromagnetic Scattering Problems 3.1. Introduction 3.1.1. General Discussion 3.1.2. Computational Aspects 3.2. Theory 3.2.1. Matrix Formulation 3.2.2. Evaluation of the Transition Matrix 3.2.3. Application to Special Geometries 3.2.4. Results for Finite Cylinders and a Cone-Sphere 3.3. Organization of the Computer Program 3.3.1. Introduction 3.3.2. Glossary of the Subroutines 3.3.3. The Input Routine 3.3.4. Calculation of End Points and Spacing for Integration 3.3.5. The First Control Routine 3.3.6. Associated Legendre Functions 3.3.7. Bessel Functions 3.3.8. Recursion Relationships for Bessel and Neumann Functions 3.3.9. Generating the Body Shape 3.3.10. First Matrix Printout 3.3.11. Printout of an Array 3.3.12. Generating the Q Matrix and the T Matrix 3.3.13. Normalizing Matrices 3.3.14. Conditioning Matrices 3.3.15. Printing the [Ti Matrix 3.3.16. Final Control Routine 3.3.17. Multiplying a Matrix Times a Vector 3.3.18. Core Dump 3.3.19. Storage Arrangements Appendix I. The Fortran IV Program Listing References 4. Integral Equation Solutions of Three-dimensional Scattering Problems 4.1. Introduction 4.2. The Integral Equations of Electromagnetic Theory 4.2.1. The Derivation of Space-Frequency Domain Integral Equations 4.2.2. The Derivation of Space-Time Domain Integral Equations 4.2.3. Tabulation of Integral Equations 4.3. Numerical Solution Methods 4.3.1. Frequency Domain Solutions 4.3.2. Time-Domain Solutions 4.3.3. Additional Considerations 4.4. Applications 4.4.1. Frequency-Domain Examples 4.4.2. Time-Domain Examples 4.5. Concluding Remarks References 5. Variational and Iterative Methods for Waveguides and Arrays 5.1. Scattering from an Infinite Grating of Metallic Strips 5.2. Variational Principle, Method of Moments and Iterative Methods 5.2.1. Variational Principle 5.2.2. Method of Moments 5.2.3. Iterative Methods 5.