Impédance d'entrée d'antennes filaires

The application of the method of moments (MOM) to the numerical solution of the Pocklington integrodifferential equations for the input impedance of wire antennas is reviewed. The general outline of the antenna problems and the principles of the MOM are summarized; the radiated field of an antenna in an infinite nonconducting medium is characterized; Galerkin and point-segment versions of the MOM are used to determine the input impedances in this case; and the analogous problem of an antenna in a conducting half-space is considered. Three numerical techniques for computing the large number of Sommerfeld integrals encountered in the case of an imperfectly conducting half-space are demonstrated and evaluated. The most efficient method giving sufficient accuracy is found to be the steepest-descent approach of Rahmat-Samii et al. (1977), based on the analysis of Debye (1909).