The extinction theorem has been applied to the study of wave scattering from a non-single-valued surface composed of an infinitely long cylinder on a flat substrate, both of which are assumed to be perfect conductors. Cylinder diameters ranging from 0.1 to 4λ (λ being the incident wavelength) are considered. The calculation method is discussed for this kind of geometry. The study has been performed for both S (perpendicular) and P (parallel) polarizations when the direction of an incident Gaussian beam is perpendicular to the cylinder axis and the direction of the scattered wave is in the plane of incidence. The surface-current density on the flat substrate and on the cylinder has also been analyzed.

Electromagnetic wave scattering from conducting cylindrical structures on flat substrates: study by means of the extinction theorem

Introductory real analysis , Introductory real analysis , کتابخانه دیجیتال جندی شاپور اهواز

Introductory Real Analysis. By A. N. Kolmogorov and S. V. Fomin, translated by Richard A. Silverman. Pp. xii, 403. (Prentice-Hall Inc.)

A new surface integral equation formulation is presented for characterizing electromagnetic radiation by conformal microstrip arrays on finite curved bodies of arbitrary shapes. The surface equivalence principle is used to reduce the original problem to two equivalent problems, one for the external medium and another for the internal medium. Electric field integral equations are applied to the conducting surfaces, and weighted sums of the field integral equations corresponding to the external and internal dielectric regions with appropriate weighted coefficients are applied to the dielectric interface. The integral equations are solved via the method of moments (MoM) procedure, to which the memory requirement and computational complexity pertinent is reduced by employing the adaptive integral method (AIM). Numerical results are presented to demonstrate the validity and accuracy of the method.

Analysis of Radiation Characteristics of Conformal Microstrip Arrays Using Adaptive Integral Method

An exact dual series solution of a plane wave incident on a coaxial dielectric circular cylinder imbedded in a semicircular gap of a ground plane is presented. Both TM and TE cases are considered here. The scattered field is represented in terms of an infinite series of cylindrical waves with unknown coefficients. By applying the boundary conditions and employing the partial orthogonality of the trigonometric functions the scattering coefficients are obtained. The resulting infinite series is then truncated to a finite number of terms to produce numerical results. For the sake of comparison with the published data some special cases are introduced first. The comparisons showed excellent agreement in all cases. >

Electromagnetic scattering from a coaxial dielectric circular cylinder loading a semicircular gap in a ground plane

The copolarized backscattered intensity from surfaces composed of metallic particles on conducting flat substrates is analyzed experimentally as a function of the incidence angle. The analysis is done for particle sizes smaller than, comparable to, and larger than the incident wavelength (0.633 μm) and for low particle surface densities. Numerical calculations based on the extinction theorem for a onedimensional surface model consisting of an infinitely long cylinder located on a flat substrate for the same optical constants used in the experiment are also presented for qualitative comparison with the experimental results. This serves to analyze the effect of particle aggregation. For the surfaces with particles smaller than the incident wavelength, conclusions are drawn concerning the possible relevance of this study in radar wave scattering from the sea surface.

Backscattering from particulate surfaces: experiment and theoretical modeling

A rigorous field analysis of the problem of scattering from a dielectric cylinder partially embedded in a perfectly conducting ground plane, and excited by a magnetic or electric line current in the free space outside the dielectric cylinder, is given in this paper. The dielectric medium is assumed to be linear, homogeneous, isotropic, although not necessarily free from losses. A field equivalence theorem is utilized to derive, for each excitation, an integral equation for the equivalent magnetic current on the dielectric interface, which is later solved using Galerkin's method. The equivalent magnetic currents are then used to determine the scattered field everywhere outside and inside the dielectric cylinder. Numerical results for the equivalent magnetic currents and far scattered field patterns are given. The resonances of the partially embedded dielectric cylinder are also defined and computed for both polarizations.

Scattering from a Dielectric Cylinder Partially Embedded in a Perfectly Conducting Ground Plane

A rigorous field analysis of the problem of two identical perfectly conducting parallel wedges with dented edges loaded with a dielectric cylinder, and excited by an electric or magnetic line current in the upper sector, is given in this paper. The dielectric medium is assumed to be linear, homogeneous, isotropic and free from losses, whereas the mediums of the upper and lower sectors are free space. A field equivalence theorem is used to derive, for each excitation, a system of coupled integral equations for the equivalent magnetic currents on the dielectric interfaces, which is later solved using Galerkin's method. The fields and powers transmitted into the lower sector, hence the transmission coefficients, for both polarisations are subsequently determined in terms of the equivalent magnetic currents on the lower dielectric interface. The analysis is then specialised to the problem of a slit loaded with a dielectric cylinder, as well as to the case of plane wave excitation. Sample numerical results for the dielectric-loaded double dented wedge and slit problems in the case of plane wave excitation are also given.

Electromagnetic diffraction by two perfectly conducting wedges with dented edges loaded with a dielectric cylinder

The quasi-TEM characteristics of a class of cylindrical microstrip lines are rigorously determined. The class of microstrip lines considered consists of multiple infinitesimally thin strips on a multilayered dielectric substrate on a perfectly conducting wedge. Expressions for the potential distribution inside and outside the dielectric substrate, charge distribution on the strips, and capacitance matrix of the microstrip lines are derived. The problems of a microstrip line on a cylindrically capped wedge and on a cylindrical dielectric substrate on perfectly conducting core are also considered as special cases. Sample numerical results based on the derived expressions are given and discussed. >

H.A. Auda

Papers

Scattering from a Dielectric Cylinder Partially Embedded in a Perfectly Conducting Ground Plane

Electromagnetic diffraction by two perfectly conducting wedges with dented edges loaded with a dielectric cylinder

Multiple microstrip lines on a multilayered cylindrical dielectric substrate on perfectly conducting wedge