In this paper we describe a numerical method for determining the wideband impedance of a transient antenna, based on a method of moments solution of the time-domain electric field integral equation. The impedance is estimated from the antenna's response to a short-pulse transient excitation; the current is determined directly from the solution of the electric field integral equation and the potential difference between the antenna arms is determined from an integration of the electric near-field. Particular attention is paid to the form of the singular near-field integrals and an alternative representation is given for these in terms of non-singular boundary integrals. The approach described in this paper has several advantages over the previous numerical approach of  and is validated against a variety of canonical antennas, including directive and omnidirectional transient radiators. The present numerical method is shown to provide an accurate estimate of the characteristic impedance of such canonical structures (to within 3 % of the known impedance).
|Number of pages||25|
|Journal||Journal of Electromagnetic Waves and Applications|
|Publication status||Published - 1998|