Radiation and scattering by thin wires with a dielectric coating—a finite‐difference time‐domain approach

Abstract

This Letter discusses the computation of the scattering and radiation by thin wires with a nondispersive dielectric coating using the finite‐difference time‐domain method. A Fourier transform is then performed on the time‐domain results to obtain the scattering and antenna radiation patterns in the frequency domain.

The Treatment of Thin Wires in the FDTD Method Using a Weighted Residuals Approach

“…It was found that the results from [11] were indistinguishable from those obtained using the method of [12] so only the latter are included in the figures.…”

“…Calculations were performed using standard FDTD, method 1 as described in [7], method 2 as described in [12], and method 3 as presented in this contribution. It was found that the results from [11] were indistinguishable from those obtained using the method of [12] so only the latter are included in the figures.…”

“…Expanding in a set of basis functions, gives (9) Taking the inner product of both sides with a weighting function , gives (10) or equivalently (11) Following a similar procedure, the update equation for can be written as (12) where is the assumed current density distribution. Note that, whereas in reality, the current is concentrated at the position of the wire, in the formulation of [7] it is considered to be distributed throughout a cylinder surrounding the wire, the shape of which is defined by the choice of basis function, .…”

“…This approach involves the introduction of an extra differential equation which relates the charge and current on the wire to the surrounding electric field. 2) Introduced by Umashankar and Taflove et al [11] in 1987, [2] in 1988, and later extended by Boonzaier [12] Douglas [13], Makinen [14], Bingle [15], and Nadobny [16] based on the contour integration interpretation which involves field integration over the edges and faces of the cells. 3) Introduced by Railton [3] in 1994 and extended by Craddock [4], in 1998 based on modifying the basis and weighting functions in the WR interpretation.…”

Generation of FDTD subcell equations by means of reduced order modeling

“…In [2] the field assumption of the tangential magnetic and the radial electric field near a thin wire were incorporated in the update equations. Later, these subcell models were improved for wires with dielectric coatings [3], for wire end effects [4] and for bundles of wires [5]. A lot of researchers have also investigated the development of subcell models for thin slots.…”