Creeping waves propagate in the shadow along the surface of a convex body. In the case of a perfectly conducting body coated with high index anisotropic dielectric, this surface can be described by anisotropic impedance boundary condition. In a previous paper the general case of anisotropic impedance was studied. In this paper we discuss a special case characterized by a degenerated impedance matrix. The ansatz for ordinary creeping waves does not allow the asymptotics to be constructed and a new ansatz is suggested. In contrast to the usual one, this ansatz contains an additional quick factor proportional to k1/6 (where k is the wavenumber). As a result, the field is described by an asymptotic sequence in inverse powers of k1/6 . We derive the principal order term of the asymptotics and discuss specific properties of creeping waves on a surface with degenerated impedance.

Fractional curl operator has been utilized to wave propagation in lossless, isotropic, homogeneous and reciprocal chiral medium when it contains interfaces. The fractional solutions for the corresponding standing wave solution and transverse impedance are determined. Equivalent fractional non-symmetric transmission line has also been analyzed.

A general method is introduced to frequency domain analysis of lossy Inhomogeneous Planar Layers (IPLs). In this method, the IPLs are subdivided to several thin homogeneous layers, at first. Then the electric and magnetic fields are obtained using second order finite difference method. The accuracy of the method is studied using analysis of some special types of IPLs.

Permittivity and conductivity studies of corn syrup in various concentrations are performed using coaxial cavity perturbation technique over a frequency range of 250 MHz-3000 MHz. The results are utilized to estimate relaxation time and dipole moments of the samples. The stability of the material over the variations of time is studied. The measured specific absorption rate of the material complies with the microwave power absorption rate of biological tissues. This suggests the feasibility of using corn syrup as a suitable, cost effective coupling medium for microwave breast imaging. The material can also be used as an efficient breast phantom in microwave breast imaging studies.

In this work, we present a semi empirical approach and the analytical model on how to predict the total path loss in various indoor communication links, taking into account the new analytical methods of the derivation of the fading phenomenon between floors and along corridors, respectively. We take into account the stochastic method of slow and fast fading estimations, caused by diffraction and multipath phenomena, respectively. The statistical parameters required for statistical description of the diffraction and multipath phenomena, such as the standard deviations of the signal strength due to slow and fast fading are obtained from the corresponding measurements. The path loss characteristics together with evaluated parameters of slow and fast fading give a more precise link budget predictor, and obtain full radio coverage of all subscribers located in the area of service inside each building. Based on strict and completed path loss prediction, an algorithm of link budget performance is presented for different scenarios of radio propagation within indoor communication links. Results of proposed unified approach are compared with the analytical Bertoni's model, which is well-known and usually used in link budget design in various indoor environments. The results are also compared with measurements carried out for different propagation scenarios, along corridor and between floors, occurred in the indoor communication channels. A better agreement with experimental data is obtained compared to the model in consideration.

The goal of the present paper is two folded. The first, the methodological one, is the complementation of well established in diffraction theory of gratings C method with certain elements of spectral theory and the development of interactive numerical algorithm that made feed back conjunction between diffraction and spectral problems. As a natural result the second goal appeared: the appearing of such tool for numerical experiments resulted in profound qualitative and quantitative study of rather peculiar phenomena in resonant scattering from periodic surface. Special attention has been paid to the investigation of electromagnetic waves diffraction from periodic boundaries of material with single and double negative parameters.

We present an efficient modal method to calculate the two-dimensional Green's function for electromagnetics in curvilinear coordinates. For this purpose the coordinate transformation based differential method, introduced for the numerical analysis of surface-relief gratings, is directly used with perfectly matched layers (PMLs). The covariant formalism Maxwell's equations, very convenient for the non-orthogonal coordinates formulation, also gives an unified analysis of PMLs. Numerical results for a line source placed above a perfectly conducting corrugated surface are presented.

To model periodic structures with oblique incident waves/scan angles in FDTD, the field transformation method is successfully used to analyze their characteristics. In the field transformation method, Maxwell's equations are Floquet-transformed so that only a single period of infinite periodic structure can be modeled in FDTD by using periodic boundary conditions (PBCs). A new discretization method based on the exponential time differencing (ETD) algorithm is proposed here for the discretization of the modified Maxwell's equations in the periodic FDTD method. This new discretization method provides an alternative way to discretize the modified Maxwell's equations with simpler updating forms that requires less CPU time and memory than the traditional stability factor method (SFM). These two methods have the same numerical accuracy and stability in the periodic FDTD method. Some validation cases are provided showing perfect match between the results of both methods.

Optical properties of generalized dielectric Fibonacci multilayer generated by the rule S_l+1 = Sⁿ _l S^m _l-1 with a pair of positive integers m and n were studied. The initial generations S1 and S2 are taken as S₁ = H and S₂ = L where H and L are two elementary layers with refractive indices n_L = 1.45 and n_H = 2.3, respectively. In the following numerical investigation, we chose SiO₂ (L) and TiO₂ (H) as two elementary layers. We use the so-called "antitrace" map to determine the transmission spectra of the structures. Based on the representation of the transmittance spectra in the visible range an analysis depending on the pair (n,m) is presented. We show that the whole structure Sⁿ _l S^m _l-1 has an interesting application for well selection pairs (m, n) values.

In the present paper, a combined method of auxiliary sources (MAS)-reaction matching (RM) approach is presented for the analysis of arrays of arbitrarily located cylindrical dipoles. It is shown that the addition of auxiliary monopole terminal sources to each array element results in a superior solution with regard to the numerical stability of the computed quantities, the behavior of the current distributions of the array elements and the resulting errors of the electric field boundary condition. Numerical results are presented for various representative array configurations, in order to illustrate the features of the proposed method and exhibit its advantages over conventional Method of Moments (MoM) schemes, especially in cases of moderately large-scale arrays. Finally, a few concluding remarks are discussed.

In the present paper a simple model has been given to simulate the signal propagation through cross orthogonal coupled strip lines in multilayer PCB board. First the structure has been analyzed using a full wave software (such as microwave office) then a simple and suitable lumped equivalent circuit is proposed for the coupled cross talk region. The values of the lumped equivalent circuit are then obtained using a simple method. These values are then optimized to fit the S-parameters obtained using full wave analysis. Finally the s-parameters of this equivalent circuit compared with the results of full wave simulations. The results show good agreement up to some GHz.

Four-dimensional differential-form formalism is applied to define the duality transformation between electromagnetic fields and sources. The class of linear media invariant in any non-trivial duality transformation is labeled as that of self-dual media. It is shown that the medium dyadic of a self-dual medium, which represents a mapping between the two electromagnetic field two-forms, satisfies a quadratic algebraic equation. Further, it is shown that fields and sources in a self-dual medium can be decomposed in two uncoupled sets each self-dual with respect to a duality transformation. Also, for each of the decomposed fields the original medium can be replaced by a simpler effective medium. Splitting the electromagnetic problem in two self-dual parts can be used to simplify the solution process because differential equations for fields are reduced to those with second-order scalar operators. This is applied to find plane-wave solutions for the general self-dual medium.

Weak signal detection and localization are basic and important problems in radar systems. Radar performance can be improved by increasing the receiver output signal-to-noise ratio (SNR). Localizing the received signal is an important task in the detection of signal in noise. Distorting the localization of the received signal can leads to incorrect target range measurements. In this paper an algorithm is described for extracting and localizing an RF radar pulse from a noisy background. The algorithm combines two powerful tools: the wavelet packet analysis and higher-order-statistics (HOS). The use of the proposed technique makes detection and localization of RF radar pulses possible in very low signal-to-noise ratio conditions, which leads to a reduction of the required microwave power or alternatively extending the detection range of radar systems.

A method is proposed for analysis of arbitrarily loaded lossy and dispersive nonuniform single or coupled transmission lines. In this method, the transmission lines are subdivided to several uniform sections, at first. Then the voltage and current distributions are obtained using second order step-by-step numerical integration (second order finite difference method). The accuracy of the method is studied using analysis of some special types of single and coupled transmission lines.

The inductive effect of near-end crosstalk for a category five unshielded, twisted-pair cable has been verified using the electromagnetic topology simulation method. Crosstalk reduction and its dependency on such parameters as driving signals, circuit configuration and impedance, are studied. The simulation results are consistent with analytical analysis. Results show that the straight- through, differential-generator, twisted-pair receptor model is the most effective configuration to control the near-end crosstalk level. This is due to the influences from both the neutralizing mutual inductance and the single current generator. The simulation results also show that electromagnetic topology-based predictions are valid only for cables that are electrically short. Simulations are carried out using a compaction scheme with a single equivalent circuit. As a result, the unshielded, twisted-pair cable portion of the circuit can be combined with a larger network for analyzing the overall response of the entire network system.

This paper is concerned with the diffraction of an electromagnetic wave by a perfectly conducting half-plane in a homogeneous bi-isotropic medium (asymptotically). Similar analysis in a source-free field is done in S. Asghar and A. Lakhtakia (1994), Planewave diffraction by a perfectly conducting half-plane in a homogeneous bi-isotropic medium. Int. J. Appl. Electromagnetics in materials, 5, (1994), 181-188. In this paper attention is focused on the wave coming from a line source. The objective is to study the scattering of an electromagnetic wave from the boundary of a half-plane and thereby to provide a theoretical framework for the line source diffraction asymptotical ly. In far field approximation it is shown that an incident wave coming from a line source behaves like a plane wave. The scattered field is calculated by using the Fourier transform and the Wiener-Hopf techniques. The scattered field in the far zone is determined by using contour integration.

In this paper, a fast method is presented to model the forward propagation above Gaussian rough surfaces and taking into account atmospheric refraction. The method is based on the Discrete Mixed Fourier Transform (DMFT) solved by the Parabolic Wave Equation, in which the Ament boundary condition with shadowing effect is used at grazing angle. In this model, for a bistatic configuration, the surface height PDF of the illuminated points is derived and it is introduced in the boundary condition. Examples demonstrate the capacities of the method to compute propagation factor above rough surfaces following Gaussian statistics and Gaussian height correlation and the proposed method is validated by comparison to a Monte Carlo approach.

The complete set of dyadic Green's functions (DGFs) for an electrically gyrotropic medium is obtained using a new formulation technique, which consists of a matrix method with dyadic decomposition in the k-domain. The analytic expressions for DGFs are represented in a unique form in terms of characteristic field vectors that exist in an electrically gyrotropic medium. It is shown that the dyadic decomposition greatly facilitates the calculation of an inverse operation, which is crucial in derivation of Green's functions. The DGFs found here can be used to solve electromagnetic problems involving the ionosphere and new types of anisotropic materials such as ceramics and advanced composites.

One of the most interesting and peculiar phenomena of Quantum Mechanics is the interference (I ) induced by the electrons. Strangely enough, though the electrons are real particles, they often behave just like waves. From the point of view of the classical mechanics the I induced by the electrons is unexplainable, however it is solved mathematically using the formalism of quantum mechanics and applying Schrödinger's equation. The quantum solution of the problem is clear and elegant, especially from a mathematical point of view, however it still leaves some perplexities as to understand how exactly the phenomenon happens. We will make a hypothesis trying to understand the undulation phenomenon of the electron: it is really a strange and mysterious phenomenon. Maybe if we consider that the electron, just as the baryons and the mesons, might be made of smaller particles (saving the integrity of the unity of the negative electrical charge and the other Laws of Conservation), we could understand more easily how a single electron can go through two close holes at the same time. Analogously we could better understand another very particular quantum phenomenon carried out mainly by electrons, that is the tunnel effect. In this case, though the particle does not have enough energy to go through the potential barrier, though it does not have any material possibility to pass through a layer which does not have any hole, after several "attempts" the particle will manage to pass through the barrier anyway, as it had dug a tunnel, or as it had managed to find a "breach" in the wall. In this phenomenon too, though we can explain it from a mathematical point of view, using the equations of the quantum mechanics, it is still not clear how actually the electron manages to have an undulation behaviour.

In this article, we propose to apply the Gabor expansion to describe magnetic and electric currents given on a regular curved interface in dimension 2. From this description, we show that the computation of the current radiation can be performed by the introduction of a new kind of gaussian beams. We call them the conformal gaussian beams. Their analytic formulation is obtained using an asymptotic evaluation of the radiation integrals. Their properties are discussed and an application example is presented.