Treatment of transient diffraction and radiation problems by SEM /Singularity Expansion Method/

An infinitely thin linear antenna with monochromatic sinusoidal current distribution is considered, and the response of this antenna to arbitrary impulse excitation is investigated. Taking into account the finite thickness of the antenna leads, through the formulation of an integral equation for the Laplace-transformed current, to a representation of the same in terms of the poles of the admittance matrix in the complex s-plane, and hence in the time domain to an expansion in terms of the damped sinusoidal oscillations. It is shown that in the limit of an infinitely thin linear antenna, this corresponds to a Fourier series expansion of the impulse response of the antenna.