Efficient analytical‐numerical modelling of ultra‐wideband pulsed plane wave scattering

Abstract

SUMMARY Ultra-wideband (UWB) pulsed plane wave scattering from a large but finite strip grating in free space is analysed in the frequency domain via decomposition into plane wave spectra, implemented numerically by the method of moments, and then inverted into the time domain (TD). To make this procedure practical under UWB conditions, closed form expressions are derived for interaction integrals involving widely separated expansion and testing functions. These closed forms are based on a judicious choice of the basis functions, and on asymptotic methods for reducing the integrals. Although large separation distances are assumed, the expressions have been found to be accurate for separations as small as 0-1 wavelengths. The TD self terms can also be evaluated efficiently. To test the frequency domain algorithm, comparisons are made with available data in the literature for surface currents and far-field scattering from multiple strips. New short pulse TD results are shown as well.

A truncated Floquet wave diffraction method for the full wave analysis of large phased arrays. I. Basic principles and 2-D cases

“…This position-independent current is taken to be that on the central element of a similar finite, but smaller grating; this latter is analyzed with an element-by-element MoM with a reduced computational cost. This approach is a clever way of exploiting a very efficient version of the element by element 2-D MoM devised by the same authors [10] and is an alternative implementation of the basic windowing approach, which differs from [2] and [3] for the choice of the position-independent current, which is obtained from the infinite periodic problem in [2] or via active Green's function in [3]. However, the use of (indeed pioneering) asymptotic constructs in [6] might lead to equivocate techniques and objectives, presented in [6] and in the present work.…”

“…T HE electromagnetic modeling of large finite arrays as well as the scattering by finite periodic structures is an important topic for a large variety of engineering applications and has been the object of many recent investigations [1]- [10]. A rigorous analysis based on an element-by-element method of moments (MoM) becomes computationally difficult when the size of the array increases.…”