We describe several numerical techniques for electromagnetic modeling of large and complex antenna problems, which require a large number of DoFs to describe them, and hence, they are CPU time- and memory-intensive when conventional methods are used to tackle them. We describe the characteristic basis function method (CBFM) as well as the integral equation discontinuous-Galerkin technique (IEDG) for the handling of these type of problems numerically efficiently. The details of the formulations are presented and numerical examples given to validate them. For many practical applications, not only the antenna problems are of interest when they operate in either transmit or receive mode, but also when we need to design them to have a low RCS, as is frequently the case in practice. We point out that the methods described in this work are quite general and are well suited for all of these cases. Furthermore, they can be used to model antennas with arbitrary material properties, be they lossy or lossless. We also present three types of sources as excitations for generating the CBFMs for the microwave circuit and antenna problems, as opposed to RCS. We conclude that the near-field contents of the edge-port and dipole moment excitations can enhance the accuracy of the CBFM over the plane wave excitation.

Chapter Contents:

• 7.1 Introduction
• 7.2 Numerical analysis of multiple multi-scale objects using CBFM and IEDG
• 7.2.1 Introduction to CBFM and IEDG
• 7.2.2 MoM combined with CFIE
• 7.2.2.1 CFIE formulations
• 7.2.2.2 Spatial basis functions
• 7.2.3 Elements of impedance matrix of MoM
• 7.3 Acceleration of electromagnetic analysis using CBFM
• 7.3.1 Partition of CBFM
• 7.3.2 Constructing CBFs by using multiple plane-wave excitation
• 7.3.3 Generation of reduced matrix equation in the CBFM
• 7.3.4 Multi-scale discretization using the IEDG method
• 7.3.4.1 Mono-polar RWG basis function
• 7.3.4.2 Introducing the penalty term to construct the weak-form integral equation
• 7.3.4.3 Filling the element of impedance matrix
• 7.3.4.4 Computational complexity
• 7.3.5 Numerical results
• 7.3.6 Summary
• 7.4 Analysis of scattering from objects embedded in layered media using the CBFM
• 7.4.1 Introduction to CBFM analysis of the object embedded in layered media
• 7.4.2 Mixed potential integral equation for objects embedded in layered media
• 7.4.3 Numerical results
• 7.4.4 Summary
• 7.5 CBFM for microwave circuit and antenna problems
• 7.5.1 Introduction
• 7.5.2 SVD-based CBFM
• 7.5.2.1 Plane-wave excitation
• 7.5.2.2 Edge-port excitation
• 7.5.2.3 Dipole-moment excitation
• 7.5.3 Numerical results
• 7.5.4 Summary
• 7.6 Conclusions
• Acknowledgment
• List of acronyms
• References

Inspec keywords: computational electromagnetics; method of moments; electromagnetic wave scattering; Galerkin method; antenna radiation patterns; integral equations

Other keywords: near-field contents; electromagnetic modeling; characteristic basis function method; dipole moment; integral equation discontinuous-Galerkin technique; CBFM; large complex antenna problems; IEDG; RCS; plane wave excitation; numerical techniques; microwave circuit; edge-port; radar cross section

Subjects: Antenna theory; Single antennas; Integral equations (numerical analysis); Electromagnetic wave propagation