Some properties of lossless bianisotropic media

Conditions for the constitutive dyadic parameters of a lossless bianisotropic medium are derived. Applying these conditions it is shown that a conservation relation, previously shown to hold for lossless anisotropic media, also holds for lossless bianisotropic media. Further, it is shown that a lossless bianisotropic medium set in motion remains lossless.     

Dispersion relation for bianisotropic materials and its symmetryproperties

The dispersion relation for an arbitrary general bianisotropic medium is derived in Cartesian coordinates, in a form well suited to imposing the boundary conditions when dealing with layered media with planar and parallel interfaces. Special cases of practical interest are also considered. Eleven fundamental coefficient families are identified by considering in detail all the symmetries present in the dispersion relation. An ad hoc expression of the determinant of the sum of two 3×3 matrices permits the use of a simple procedure to obtain the coefficients of the dispersion equation. The discussed symmetry properties have general validity, and this technique to evaluate the coefficients may be useful in other fields of application where dispersion relations are of importance     

Unbounded and scattered field representations of the Dyadic Green'sfunctions for planar stratified bianisotropic media

This paper presents a rigorous formulation of the spectral-domain dyadic Green's functions for planar stratified bianisotropic media. The media may consist of any number of layers bounded by optional impedance/admittance walls. Both electric and magnetic dyadic Green's functions for arbitrary field and source locations are derived simultaneously. Based on the principle of scattering superposition, these dyadics are decomposed into unbounded and scattered parts. The scattered dyadic Green's functions are determined without cumbersome operations using the concepts of effective reflection and transmission of outward-bounded and inward-bounded waves. The scattering coefficient matrices are expressed in compact and convenient forms involving global reflection and transmission matrices. Corresponding to the impedance/admittance boundary walls, the global reflection matrices are related directly to the wall impedance/admittance dyadics. For illustration, the general expressions of dyadic Green's functions are applied to the configuration of a grounded bianisotropic slab embedded in isotropic halfspace     

Plane wave propagation in a uniaxial bianisotropic medium with an application to a polarization transformer

Uniaxial bianisotropic medium is a generalization of the well-studied bi-isotropic and chiral media. It is obtained, for example, when microscopic helices with parallel axes are positioned in a host dielectric in random locations. Plane wave propagation in such a medium is studied and a simple solution for the dispersion equation and for the eigenwaves are found. As a numerical example, polarization properties of a transverse wave propagating in a uniaxial bianisotropic medium is considered. The results give a simple possibility to construct a polarization transformer with a transversely uniaxial chiral medium for changing the polarization of a propagating plane wave.     

Analysis of guided waves in inhomogeneous bianisotropic cylindricalwaveguides

Electromagnetic fields in structures composed of inhomogeneous cylindrical layers are analyzed using a propagator matrix approach. The presented formulation is capable of analyzing fully bianisotropic media, where the involved propagator matrix for bianisotropic media is derived in cylindrical coordinates. The applicability of the method is demonstrated by calculating the dispersion characteristics of surface waves as well as fundamental and higher order modes on cylindrical microstrip lines on top of an inhomogeneous bianisotropic substrate     

Plane wave propagation in uniaxial bianisotropic medium

The uniaxial bianisotropic medium is a generalisation of the bi-isotropic and chiral media which recently have been subject to intensive research. Such a medium results, for example, when microscopic helices with parallel axes are positioned in a host dielectric in random locations. Plane wave propagation in such a medium is studied and a simple solution for the dispersion equation is found. Numerical examples for the wave number surfaces of the medium are given.<>     

A numerical formulation of dyadic Green's functions for planarbianisotropic media with application to printed transmission lines

An integral equation (IE) method with numerical solution is presented to determine the complete Green's dyadic for planar bianisotropic media. This method follows directly from the linearity of Maxwell's equations upon applying the volume equivalence principle for general linear media. The Green's function components are determined by the solution of two coupled one-dimensional IE's, with the regular part determined numerically and the depolarizing dyad contribution determined analytically. This method is appropriate for generating Green's functions for the computation of guided-wave propagation characteristics of conducting transmission lines and dielectric waveguides. The formulation is relatively simple, with the kernels of the IE's to be solved involving only linear combinations of Green's functions for an isotropic half-space. This method is verified by examining various results for microstrip transmission lines with electrically and magnetically anisotropic substrates, nonreciprocal ferrite superstrates, and chiral substrates. New results are presented for microstrip embedded in chiroferrite media     

Spectral dyadic Green's function formulation for uniaxial bianisotropic superstrate-substrate structure

In this paper, spectral-domain dyadic Green's functions for the time harmonic electric current source embedded in a two-layer grounded uniaxial bianisotropic media are obtained using Fourier tranform. It is shown that in the uniaxial bianisotropic medium, total spectral electromagnetic field can also be separated into the superposition of transverse electric (TE) and transverse magnetic (TM) wave. Because of the generality of constitutive relations our results include the special cases of achiral, uniaxial, reciprocal and nonreciprocal biisotropic media.

     

Integral equation solution to the guidance and leakage propertiesof coupled dielectric strip waveguides

The guidance and leakage properties of single and coupled dielectric strip waveguides are analyzed using the dyadic Green's function and integral equation formulation. Galerkin's method is used to solve the integral equation for the dispersion relation. The effects of the geometrical and the electrical parameters on the dispersion relation are investigated. A method for predicting the occurrence of leakage is proposed. The properties of the even and the odd leaky modes are also investigated. Results are compared with previous analysis and are shown to be in good agreement     

导行波在非均匀双各向异性平板波导中的传播特性

本文应用模式本征展开和模匹配方法，首先给出了非均匀双各向异性平板波导中混合模的场分布和相应的奇偶模分量色散方程．借助数值分析技术，揭示了低阶模的反射和透射系数随双各向异性介质的几何和本构参数变化规律     

The nonreciprocity of microwave transmission along a bianisotropic-ferrite metastructure

Propagation of microwaves along a plane layered structure containing a bianisotropic and a magnetized ferrite layer is theoretically investigated. The dispersion equation that allows taking into account an air gap or an active layer (SPASER) located between these layers is derived. This equation is numerically solved with allowance for the dispersion characteristics of the ferrite and bianisotropic metamaterial, and, with the help of the obtained solution, the spectra of the slowing factor and nonreciprocity parameter of the wave transmission in the structure are found. The influence of the magnitude and direction of the external magnetic field and of the gap thickness on the nonreciprocity parameter is considered. The validity of the conclusion (drawn from experiments) that it is possible to provide for the nonreciprocal transmission of signals at frequencies substantially exceeding the ferromagnetic resonance frequency attainable in the presence of the available magnetic field is confirmed.     

Interaction of electromagnetic waves with general bianisotropicslabs

An efficient, elegant, and systematic formulation technique which, combining Fourier transform with matrix analysis methods, is suitable for problems related to radiation by dipole or other sources in the presence of an arbitrarily general stratified anisotropic medium has been recently developed. This technique is adapted further extended to allow the presence of general bianisotropic media described by four tensors with no limitations on their elements. Two specific applications pertaining to some canonical problems of fundamental importance are included to exemplify the method and demonstrate its usefulness: radiation by an arbitrarily oriented elementary electric dipole source located in the vicinity of a general bianisotropic slab, either grounded or ungrounded, leading to the expressions of the dyadic Green's function of the structure, and reflection and transmission of an arbitrarily polarized plane wave incident upon such a slab, leading to closed-form concise expressions for the reflection and transmission coefficient matrices     

Nonreciprocal microwave bianisotropic materials: reciprocitytheorem and network reciprocity

There are many attempts to generalize the reciprocity theorem for bianisotropic media. With formal introduction of notion of reaction for bianisotropic media, we can formulate reciprocity conditions for the medium parameters. We can also extend the procedure used for a gyrotropic medium and consider the complementary, or the Lorentz-adjoint, bianisotropic medium, which satisfies the reciprocity theorem. Definition of the notion of reaction in bianisotropic media is, however, not so trivial. We consider some important aspects of the physical admissibility to use the notion of the reaction as a “physical observable” in bianisotropic media. The questions also arise: for what kinds of the known bianisotropic media is the reciprocity theorem physically applicable? Based on what kind of bianisotropic media, can nonreciprocal microwave devices be realized? We show that a novel class of microwave bianisotropic materials-magnetostatically controlled bianisotropic materials (the MCBMs)-are “physically justified” materials. The Onsager-Casimir principle and the notion of reciprocity are applicable in this case. New nonreciprocal microwave devices based on the MCBMs can be realized     

Time-harmonic two- and three-dimensional Green's dyadics forgeneral uniaxial bianisotropic media

A rigorous study of the Green's dyadics in two and three dimensions for general uniaxial bianisotropic media is made. The Green's dyadics are derived in the time-harmonic regime. A general uniaxial bianisotropic medium is described by eight parameters. In general, it is impossible to derive a closed-form representation of the Green's dyadics in three dimensions. In one important special case, however, where one relation is satisfied between the eight parameters, it is possible to obtain a closed-form representation     

Green dyadic for a uniaxial bianisotropic medium

An explicit expression for the Green dyadic corresponding to the axially chiral reciprocal uniaxial bianisotropic medium is derived through dyadic analysis with no recourse to Fourier transformations. The result is a generalization of the Green dyadic corresponding to the uniaxial anisotropic medium, which has been known for decades. As a verification, expressions for the field due to an axial dipole are derived and compared to those derived recently through other methods. The medium under study can be realized by laying axially parallel metal helixes in random locations in a host material. Such a medium has recently been shown to possess important polarization-transforming properties     

Scattering of obliquely incident waves by an impedance cylinderwith inhomogeneous bianisotropic coating

A propagator matrix approach for cylindrical structures is applied to solve scattering problems featuring inhomogeneous bianisotropic media. The involved propagator matrix, which describes the relation between the transverse fields at the two boundaries of an inhomogeneous cylindrical layer, is obtained by utilizing Fourier series expansions for the fields as well as material parameter functions. The presented formalism is capable of analyzing the scattering of plane waves which are obliquely incident on an impedance cylinder that is covered with an inhomogeneous bianisotropic layer. We provide typical examples showing the applicability of the method     

Field representations in uniaxial bianisotropic medium bycylindrical vector wave functions

Field representations are presented in a uniaxial bianisotropic material region. The results reveal that the solution of a source-free vector wave equation is the sum-integral form of the circular cylindrical vector wave functions in isotropic media. The application of the proposed theory to scattering is considered     

Covariant descriptions of bianisotropic media

It is suggested that a medium it which the field vectors D and H depend on both E and B but are parallel to neither be described as bianisotropic. A moving medium, even if it is isotropic it its rest frame, then appears bianisotropic to the laboratory observer. This paper gives the transformation formulas for the constitutive relations of a bianisotropic medium between inertial frames in relative motion. It circumvents the necessity of knowing the constitutive relations of the medium in its rest frame. As an application of the general formulation, the dispersion relations for plane waves in a bianisotropic medium are derived.     

Propagation of EM waves in composite bianisotropic cylindrical structures

Propagation of electromagnetic waves in a bianisotropic cylinder embedded in an unbounded bianisotropic space and enclosing an array of parallel bianisotropic circular rods is studied. Based on a separation of variables technique which is facilitated by the use of suitable translation-addition relations, the analysis ends up with an infinite homogeneous system of linear algebraic equations. All matrix elements are given by pole-free, single-term, closed-form expressions. Numerical results are presented for several cases along with comparisons with previously published data. These results reveal the possibility to dynamically control the dispersion characteristics of the structure via changes in the constitutive parameters of the materials involved.     

Propagating eigenmodes for plane waves in a uniaxial bianisotropicmedium and reflection from a planar interface

A time-harmonic electromagnetic plane wave propagating in a uniaxial bianisotropic medium is considered. Forward- and backward-propagating eigenmodes are identified, together with their dispersion equations. The eigenmodes consist of two pairs with different phase velocities, and the two components of each pair correspond to the forward and backward modes. The propagating modes are used to calculate the reflection coefficient matrix at an interface between a vacuum and a uniaxial bianisotropic half-space. Numerical results for such a reflection are presented as a function of the direction of the optical axis