Extraction of tensor parameters of general biaxial anisotropic materials

Yosef T Aladadi,Majeed A S Alkanhal

doi:10.1063/1.5130663

Abstract

This paper proposes a novel S-parameter retrieval method to extract the arbitrary permittivity and permeability tensors of general biaxial anisotropic materials. The proposed method uses three measurements of the reflection and transmission coefficients of a simple normal-incident circularly polarized plane wave. The circular polarization is employed to overcome the ambiguity attributed to the discontinuities in the extracted possible positive and negative values of the permittivity and permeability tensors for natural or synthesized anisotropic materials. The mathematical procedure of the proposed method directly relates the combined parameters deduced from the circularly polarized wave components to the tensor permittivity and permeability linear components while avoiding the need for heavy computations or optimization schemes. This simple procedure successfully overcomes the limitations to the usable frequency band and the material losses observed in previously published retrieval techniques for lossless and lossy anisotropic materials at low- and high-frequency regions. The retrieved tensor elements are validated by comparison to analytical data obtained from solving the original electromagnetic problem using the Berreman 4 × 4 matrix method after extending it to the case of circularly polarized fields.

Highlights

The fast developments in contemporary material technology are accompanied by extensive work to understand the complex characterization at terahertz (THz) frequencies of materials of interest, facilitating effective designs and applications
An analytical technique built upon the 4 × 4 matrix method was introduced in Ref. 22 to extract arbitrary permittivity and permeability tensors of lossy anisotropic materials using multiple TE and TM off-axis oblique measurements in addition to an optimization scheme
This paper presents an effective retrieval method for extracting the permittivity and permeability tensors of a general biaxial anisotropic material

Summary

INTRODUCTION

The fast developments in contemporary material technology are accompanied by extensive work to understand the complex characterization at terahertz (THz) frequencies of materials of interest, facilitating effective designs and applications. In Ref. 19, two optimization methods to minimize the relative parameter mismatch are applied to the retrieval of the constitutive tensors of the SRR structure using three obliquely incident plane wave measurements. An analytical technique built upon the 4 × 4 matrix method was introduced in Ref. 22 to extract arbitrary permittivity and permeability tensors of lossy anisotropic materials using multiple TE and TM off-axis oblique measurements in addition to an optimization scheme. This paper presents a novel tensor parameter retrieval method at THz frequencies based on circular wave incidence for homogeneous optical/electromagnetic anisotropic structures. This method is simple, requiring only three different measurements. The results of the retrieved parameters are validated by comparison to the original analytical data, and the absolute error in the permittivity and permeability tensors is computed

THEORETICAL ANALYSIS

RESULTS AND DISCUSSIONS

CONCLUSIONS