Analysis of transmitting wire antenna

Abstract

Researches and investigations in transmitting wire antenna is continuing. The term wire means metallic, highly conducting, solid or tubular electrically thin wires, i.e. wires with diameter very small compared to the length of the wire and the wavelength of an incident plane wave. When the wire element is excited at one or more electrically small regions along the length, it behaves as a transmitting antenna. The accurate solution of the antenna characteristics can be obtained from the surface current, which can be obtained from Maxwell's equation subject to boundary conditions. This result an integral equation of current which can be solved using numerical method. The numerical methods are so simple and it can be applicable to many configurations. In this work a moment based numerical technique which consists of expanding the unknown quantity in to a series with unknown coefficients. The expansion is introduced in the integral equations and a testing procedure is performed and that has been used to evaluate the current distribution. First theoretical analysis with appropriate derivations are presented. Then a Matlab code to model the current distribution is developed. The algorithm to evaluate integral is based on moment method and Pocklington's equations. Length of the wire is taken as 0.47λ and area of cross-section as 0.005λ. Frequency is selected as 3MHz.