Temporal near fields of a missile structure under plane wave illumination

Abstract

Summary form only given. Discusses the interaction of a transient EM field with a conducting cylindrical body. The physical features of the body-of-revolution (BOR) model and the characteristics of the incident wave are of prime importance with regard to the means of interaction. The conducting BOR studied is a simplified missile structure consisting of a straight cylinder which is closed with an endcap on one end and linearly-tapered to a circular aperture on the opposite end. Different types of incident ultra-wideband plane waves are considered. The standard Gaussian temporal waveshape is investigated along with a wave that resembles a short single cycle sine wave (designated as the non-Gaussian plane wave). The structure response which is of particular interest is the axial electric field at the center of the BOR aperture which represents the field in the nose cone of the missile. The fins and other external details are omitted in this model since the dominant structure resonance corresponds to longitudinal skin currents occurring at a frequency where the axial length of the BOR is approximately one-half wavelength. The time domain response of the BOR to a given incident pulse is determined via the following approach. The response of the BOR to a true time-domain impulse (flat spectrum) is computed in the frequency domain via the method of moments. The range of frequencies computed is governed by the upper limit on the spectral content of the incident pulse. The product of the incident pulse spectrum and the impulse spectral response is found and the overall time-domain response is determined.