Condon's model on optical rotatory power and causality - a scientific trifle

In this paper some of the consequences of the model for optical activity suggested by Condon are analyzed. The scattering problem is solved for a semiinfinite and a finite homogeneous slab, respectively. Specifically, the noncausal effects of this model are demonstrated. These effects are disturbingly large for many materials and the model has to be discarded as unphysical. The rotation of the polarization plane is shown to agree with the fixed frequency results when the transient part of the solution has died out. Moreover, a new delta sequence that is associated with the Fresnel integrals is analyzed

Homogenization of spherical inclusions

The homogenization of cubically arranged, homogeneous spherical inclusions in a background material is addressed. This is accomplished by the solution of a local problem in the unit cell. An exact series representation of the effective relative permittivity of the heterogeneous material is derived, and the functional behavior for small radii of the spheres is given. The solution is utilizing the translation properties of the solutions to the Laplace equation in spherical coordinates. A comparison with the classical mixture formulas, e.g., the Maxwell Garnett formula, the Bruggeman formula, and the Rayleigh formula, shows that all classical mixture formulas are correct to the first (dipole) order, and, moreover, that the Maxwell Garnett formula predicts several higher order terms correctly. The solution is in agreement with the Hashin-Shtrikman limits

On the generation of surface waves in frequency selective structures

In this paper, we discuss and analyze the criteria for the existence and the generation of surface modes in dielectric slabs with and without metallic layers (frequency selective structures, FSS). The material parameter of the slab is in general bianisotropic, but the examples and the numerical computations show only isotropic materials. It is shown that there are three different categories of resonances occurring in power transmission and power reflection in a FSS, i.e., 1) resonances in the array, 2) surface wave excitations, and 3) onset of grating lobes

Homogenization of corrugated interfaces in electromagnetics

A surface with periodic corrugations of suffciently small periodicity is shown to be electromagnetically equivalent to an inhomogeneous transition region (slab). Explicit expressions for the inhomogeneous transition region are found for one-dimensional corrugations and for two-dimensional corrugations a local elliptic problem has to be solved in order to find the equivalent electromagnetic properties. The homogenized surface can be characterized by its surface impedance dyadic or its reflection dyadic. A few numerical examples illustrate the theory

Electromagnetic scattering by layered cylinders --- low frequency reduction of RCS

In this paper we present two different ways of reducing the radar cross section (RCS) of thin metallic wires at low frequencies. This reduction is achieved by adding a dielectric coating on the wire. The entire cylindrical structure is finally protected by a thin exterior non-magnetic dielectric layer (eagle skin). The contribution to the RCS has either an electric or an magnetic origin. To reduce the RCS it is possible to chose material parameters so that both the electric and the magnetic contributions vanish. This leads, however, to non-physical material parameter values. The underlying principle in the second method is to chose material parameters in the dielectric coating such that the electric and magnetic contributions annihilate each other. Fortunately, this annihilation can be obtained with physically realistic material parameters. Explicit numerical examples illustrate both ideas

Time-domain methods for complex media

The objective of this paper is to review the fundamental macroscopic modeling of linear complex materials in a time domain formulation. Based upon a set of basic assumptions, the general form of the constitutive relations for a linear complex media in the time domain is formulated. Furthermore, constraints on the possible form of the susceptibility kernels for a passive medium are presented. For completeness, the corresponding constraints for a reciprocal medium are also given

The polarizability and the capacitance change of a bounded object in a parallel plate capacitor

A method to solve the change in capacitance of an object in a parallel plate capacitor is developed. The integral representation of the potential is exploited in a systematic way to solve the potential everywhere inside the capacitor. In particular, the change in capacitance is extracted. The method shows similarities with the null field approach to solve dynamical problems

Transient electromagnetic waves and inversion techniques

This paper reviews an efficient inversion technique for complex media utilizing transient electromagnetic scattering data. The approach to solve the scattering problems (direct and inverse) relies on a wave splitting technique and an invariant imbedding technique. The analysis is illustrated by a numerical example

Multiple scattering by a collection of randomly located obstacles Part V: Low order contributions to the coherent fields

The aim of this paper is to find appropriate approximate expressions of thecoherent electromagnetic field scattered by a particulate slab. The exact solution of the coherent electric field to the multiple scattering problem in the slabis determined by the solution of a set of integral equations. By iterating theintegral equations, an approximate solution is obtained, which approximatesthe solution of the scattering problem very well for tenuous media. The firstiterate is well documented in the literature and consists of the single scatteringcontribution to the reflected and transmitted fields. The second term involvesdouble scattering contributions and is more complex. However, the result hasan analytic solution, which makes it possible to trace different contributionsto the final solution. Several numerical illustrations are presented, which showthe accuracy and use of the approximate solutions