TE Plane Wave Research Articles

TE-Plane Wave Scattering from a Dielectric-Loaded Semi-Circular Trough in a Conducting Plane

The theoretical behavior of TE-plane wave scattering from a dielectric-loaded semicircular trough in a conducting half-space is investigated. The dielectric loading is made of a circular cylinder which is partially buried in a semi-circular trough in a perfectly conducting plane. The scattered field is numerically evaluated to investigate the angular scattering pattern under the various dielectric loading conditions. The presence of the dielectric loading in the trough can substantially affect the angular scattering behavior. The difference between the TE and TM-scattering angular patterns is also observed. The field magnitude inside the trough is found to be much greater than the outside, thus indicating that the trough focuses the incident beam inside the trough.

TE-scattering from dense homogeneous infinite dielectric cylinders of arbitrary cross-section

A numerical approach to obtain the fields scattered by a homogeneous dielectric cylinder of arbitrary cross section which is illuminated by a TE plane wave is presented. The equivalence theorem is used to transform the problem of solving Maxwell's equations in the whole space, subject to the conditions imposed by the presence of the cylinder and the incident field, into an operator equation for the volume polarization currents in the cylinder. A set of expansion functions is then used to solve the problem using Galerkin's technique. These expansion functions are obtained by dividing the cylinder cross-section into a number of triangular patches and defining, for each node in the mesh of triangles, a basis function which depends on the dimensions of the triangles attached to it. This basis function is divergence-free for all the internal nodes, with surface charges associated to the external nodes only. The computed results include the radar cross sections. Several geometries are studied, and the computed results are compared with exact or numerical results.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Application of OSRC operator of third order to electromagnetic scattering from conducting or dielectric cylinder

The on-surface radiation condition (OSRC) operator of the third order is derived for improving the calculation accuracy of the scattering from a two-dimensional homogeneous dielectric cylinder illuminated by a TM or TE plane wave. The numerical results of radar cross-section (RCS) of this cylinder are given.

An Iterative Technique Based on the Method of Least Squares Applied to Scattering Problems Using the k-Space Approach

An iterative technique based on the method of least squares and utilizing variational trial functions is presented. It is applied in the solution of scattering problems involving arbitrarily shaped homogeneous or inhomogeneous penetrable obstacles, utilizing a volume formulation and the k-space approach. The method minimizes a squared error over subspaces of the range of the operator, and is guaranteed to converge under certain conditions. For the class of problems for which it was designed, namely scattering problems for dielectrics using a volume formulation, the method performs better than other iterative techniques. Numerical results are presented for infinitely long homogeneous circular cylinders with TE plane wave excitation. A comparison of the performance of the iterative technique with the conjugate gradient method is made. Modifications of the iterative method which involve increasing the number of trial functions are discussed and numerical results are presented which demonstrate the effects of...

Electromagnetic Penetration into a Conducting Circular Cylinder through a Narrow Slot, TM Case

A procedure is presented for calculating the electromagnetic field in the vicinity of an infinitesimally thin conducting circular cylindrical shell with an infinitely long slot illuminated by a TE plane wave. This field is the short-circuit field plus the field due to the slot. The short-circuit field is the field that would exist if there were no slot. The field due to the slot stems from the Φ -component of the electric field in the slot. Approximated by a linear combination of expansion functions that satisfy the edge conditions, this field component is determined by testing the equation of continuity of the axial magnetic field in the slot with non-negative powers of Φ where |Φ| is the angular distance from the center of the slot. Alternative expansion functions are introduced to preserve the accuracy of the solution in the vicinity of an internal resonance. Containing the resonant electric field, the first alternative expansion function is normalized so that its axial magnetic field remains finite as...

Electromagnetic Fields Induced Inside Arbitrary Cylinders of Biological Tissue (Short Papers)

The electromagnetic field induced inside arbitrary cross-sectioned cylinders of biological tissue is analyzed by integral equation and moment method techniques. A TM or TE plane wave incidence is assumed, and the cylinders consist of bone or muscle and may be multiIayered. The integral equations are of the surface type, and are derived via vector Green's theorem and boundary conditions. Surface and interior fields for both a one-layer and two-layer circular cylinder are found to have excellent agreements with the exact eigenfunction expansion results, thus validating the numerical method. Extensive results are presented for arbitrary cross-section cylinders, with among these an arm model composed of an elliptical outer muscle layer and a circular bone at the center. The field plots throughout the cylinder interior thus obtained should be useful in diagnostics of microwave hazards, particularly in predictions of the so-called "hot spots."

Transient currents on a cylinder illuminated by an impulsive plane wave

An analytical and numerical study of the transient current density induced on a perfectly conducting circular cylinder has been carried out. Both TE and TM incident plane waves with impulsive time dependence are considered. Complete closed form expressions for the TE and TM current density at all points on the cylinder and for all time values are obtained by a functional interpolation of both large and small time asymptotic solutions. The complete expressions should he useful in future transient radar scattering problems for approximating the transient current behavior on portions of a complex scatterer. The numerical results are presented in the form of "snapshots" of the current density at specific instants of time. The results are interpreted in terms of specular reflection and creeping waves. The creeping wave pulses are seen to be a continuation of pulses generated on the illuminated surface; their propagation into the shadow region is a highly dispersive phenomenon. The natural mode spectrum is seen to have both discrete and continuous components with the response at very large times determined by the latter.