Aperture Integral Equation Research Articles

Moment Method Analysis of Corrugated Surfaces Using the Aperture Integral Equation

This communication describes a method of moments formulation to analyze the scattering from corrugated surfaces. The approach is based on the aperture integral equation. Such approach decouples the analysis of the impedance effect of the grooves from the external coupling among grooves and allows us to deal accurately with grooves of any shape. Advantage is taken of the geometrical properties of the problem to solve it efficiently using a conjugate gradient-FFT algorithm.

Coupling onto Wires Enclosed in Cavities with Apertures

This paper presents a hybrid numerical method for the electromagnetic field coupling into apertures residing on the surface of rectangular cavities. The cavity may enclose wires and cables that are typically modeled via transmission line approaches. Coupling into the cavity is analyzed via the moment method along with the cavity Green's function to find the aperture fields whereas Pocklington's integral equation is adapted for the wire/cable currents. The combined wire and aperture integral equation system can be solved directly or by decomposing it into the aperture and wire subsystems. The latter decomposition leads to a two-step or a multistep iterative approach for the solution of the aperture and wire currents. Of importance in this analysis is the use of acceleration algorithm for improving the convergence of the modal Green's function series after the application of the moment method. Issues associated with the large condition of the matrix systems near cavity resonances are also addressed.

Field Generated by a Magnetic Line Source Embedded in a Semi-Infinite Dielectric Slab

In this paper, a numerical solution procedure is presented to calculate electromagnetic fields generated by a magnetic line source embedded in a semi-infinite dielectric slab waveguide. The solution consists of a fringe aperture integral equation for magnetic currents at the edge in the plane normal to the dielectric slab waveguide. In order to construct an effective numerical solution, asymptotic expressions for the field in the dielectric slab waveguide generated by the magnetic source are derived. The differences in the asymptotic expressions for the fields in a dielectric slab and a grounded dielectric slab are discussed.

High‐frequency scattering on a semi‐infinite dielectric slab with a rising ground: TM case

AbstractThe scattering of electromagnetic fields at the edge of a semi‐infinite dielectric slab on a rising ground is considered. The solution procedure is reduced to the solution of an aperture integral equation (A‐IE) for magnetic currents at the edge in the plane normal to the ground plane. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 52–55, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20373

Modelling of a microstrip antenna on a finite ground plane using the expansion wave concept and the aperture integral equation formulation

A microstrip antenna located on a finite ground plane has been analysed. The calculation is split into several steps. In the first step, the microstrip antenna on an infinite ground plane is analysed using the moment method. In the next step, the radiation pattern is calculated using ray tracing techniques. The fields in the layered structure are expanded into a finite number of expansion waves. The expansion waves propagate up to the edges of the finite ground plane, where they diffract. Diffraction coefficients for these waves are calculated using a formulation based on the aperture integral equation. The experimental results are in good agreement with the proposed model.

Hybrid thin-slot algorithm for the analysis of narrow apertures in finite-difference time-domain calculations

A technique to incorporate a half-space aperture integral equation into a finite-difference time-domain (FDTD) code based on the offset Yee mesh (see K.S. Yee, ibid., vol. AP-14, p.302-7, 1966) is presented. To introduce the technique, linear apertures that are electrically narrow in both width and depth are discussed. The method incorporates an independent time-marching solution for the aperture problem into the FDTD code so that the aperture formally does not exist within the main FDTD mesh. A feedback scheme is introduced so that full exterior and interior coupling is included in the aperture solution. The technique is particularly useful for the analysis of apertures that are narrow both in width and depth with regard to the FDTD spatial cell. Previous thin-slot methods are shown to significantly underestimate the transverse gap electric field for this case, and an explanation for this is provided with the aid of the hybrid algorithm.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>