Controlling Electromagnetic Fields with Tensor Transmission Line Metamaterials

The advent of metamaterials and transformation electromagnetics have revolutionized the use of materials in the control of electromagnetic fields. Metamaterials enabled the control of material properties, and transformation electromagnetics provided a systematic procedure for designing these materials to achieve a specified electromagnetic field distribution. Greater control over the material parameters amounts to greater control over electromagnetic fields. In particular, the ability to design anisotropic materials with spatially varying material parameters is crucial to the development of countless novel guided-wave and radiating structures.
This thesis shows how to develop electromagnetically anisotropic, inhomogeneous materials using circuit networks: tensor transmission-line metamaterials. Tensor transmission line metamaterials are circuit-based metamaterials possessing tensorial effective material parameters. They are magnetically anisotropic, and their anisotropic material parameters consist of a 2×2 permeability tensor and scalar permittivity. A theoretical basis for analyzing, synthesizing and homogenizing tensor transmission-line metamaterials is developed. Their propagation characteristics are verified through full-wave simulation and experiment.
In addition, a distinct method for arbitrarily controlling the phase progression and power flow of electromagnetic fields within a region of space is proposed. The method provides an alternative design approach to transformation electromagnetics, and it exploits an anisotropic medium's ability to support power flow and phase progression in different directions. The proposed method has proven useful in establishing aperture field profiles with arbitrary phase and amplitude distributions. Illustrative examples are introduced. Beam-formers, which can create arbitrary aperture field distributions (phase and amplitude) are reported.