Department of Radio Science and Engineering

Both isotropic and uniaxially anisotropic media capable of supporting backward waves are reviewed. Such an effect recently has been of great interest, and certain man-made composite media have been introduced under the names “media with negative refraction factor” or “left-handed materials,” effective in a certain band of microwaves. Neither of these names appears to be well founded, and “backward-wave medium” (or BW medium) is suggested instead. It is shown that, at an interface of a regular and a BW medium, Snell's law does not imply a negative refraction factor. However, the refraction is anomalous in the sense that the transmitted plane wave is a backward wave with a Poynting vector and a wave vector pointing in opposite lateral directions. The significance of the Zenneck wave and guided modes in a cylindrical guide made of BW medium is discussed. Finally, the BW property is extended to uniaxially anisotropic media, and its occurrence is studied for different value combinations of its medium parameters. It is shown that a lateral backward wave can arise when a plane wave is transmitted through an interface when one of the four parameters of the uniaxial medium is negative. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 129–133, 2001.

Plane-wave propagation is considered in a medium which is a generalization of the uniaxial chiral and the uniaxial omega medium, both of which have shown properties useful for the design of electromagnetic devices. The medium is reciprocal and it can be easily realized by mixing certain metal wire elements in a host material. The resulting bianisotropic medium is isotropic in directions perpendicular to an axis in space. Wave-number expressions are derived and numerical examples considered. © 1993 John Wiley & Sons, Inc.

Characteristics of surface wave modes on a grounded slab of negative permittivity and negative permeability parameters are investigated. It is shown that, unlike a slab with positive parameters, the dominant mode can have evanescent fields on both sides of the interface between the slab and the surrounding air. Detailed characteristics of such mode for various combinations of the slab parameters are given.

and circular structures with a rectangular type of corrugation, with and without the presence of a second Ž . smooth or corrugated conductor. 2. The exact analytic static-field solutions and Green's functions of all of these structures have been obtained. Common properties of the conformal mappings and the corresponding field distributions have been discussed, and the method of the mappings construction in the general case has been proposed.

Introduction • Theory • The waveguide with reactance boundaries • The Inhomogeneous Resonator • Conclusion Abstract • The nonstandard (general) eigenvalue problem is defined in operator by L(λ) = 0 and B(λ) = 0. • For a standard problem L is a linear function of λ and B does not depend on λ. It's shown by examples.

Perfect electromagnetic conductor (PEMC) has been introduced as a generalization of both the perfect electric conductor (PEC) and the perfect magnetic conductor (PMC). In the present paper, the basic problem of reflection and transmission of an obliquely incident plane wave at the interface of a PEMC half space or slab is considered. It is found that the field outside the PEMC medium can be uniquely determined but the interior field requires some assumptions to be unique. In particular, definition of the PEMC-medium condition as a limit of a Tellegen-medium condition and extraction of certain virtual fields (metafields) are shown to make the field inside the PEMC medium unique.

The transversely bianisotropic uniaxial medium considered in the present article can be obtained, e.g., by mixing metal helices with an isotropic base medium in such a way that the axes of the helices are randomly oriented but perpendicular to a fixed direction in space. The medium is a generalization of the well-studied chiral medium, and is somewhat similar to the recently studied axially bianisotropic uniaxial medium, which has interesting polarization properties. Plane-wave propagation in the medium is studied and the solution for the dispersion equation is given. Numerical examples for the wave numbers corresponding to the two eigenwaves of the medium are displayed. It is seen that, unlike in the axially bianisotropic uniaxial medium, there are no optical axes in the present medium, in general. © 1993 John Wiley & Sons, Inc.

The exact-image method, recently introduced for the solution of electromagnetic field problems involving sources above a planar interface between two homogeneous media, is shown to be valid also for sources located in complex space, which makes its application possible for Gaussian-beam analysis. It is demonstrated that the Goos-Hanchen shift and the angular'shift of a TE-polarized beam are correctly given as asymptotic results by the exactreflection-image theory. Also, the apparent-image location giving the correct Gaussian beam transmitted through the interface is obtained as another asymptotic check. The theory described here makes it possible to calculate the exact coupling from the Gaussian beam to the reflected and refracted beams as well as to the surface wave.

Representation of electromagnetic expressions in terms of the four-dimensional differential-form formalism has been recently shown to allow simple analysis to problems involving general classes of linear electromagnetic media. In the present paper, another class of media is defined by expressing the medium dyadic representing the mapping between the electromagnetic two-forms in terms of one dyadic representing mapping between two four-vectors. Thus, the class, labeled as that of IB-media, is represented by 16 parameters instead of the 36 of the most general bi-anisotropic medium. Condition for the medium dyadic is derived and and properties of fields in the IB-medium are discussed. † Notation adopted here follows that of . A brief introduction can be found in the Appendix of .

Applying scalarisation of the planewave fields, an expression for the reflection dyadic corresponding to the soft and hard surface (SHS) is derived, applicable for both the electric and magnetic fields of the plane wave. Eigenvectors and eigenvalues of the reflection dyadic allow one to express the dyadic in a particularly simple form in terms of circularly polarised unit vectors. The expression can be effectively applied to problems involving consecutive reflections from many SHS surfaces.