An investigation of the array of circular-loop antennas

Abstract

A circular-loop antenna composed of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</tex> elements with arbitrary circumference arranged parallel in a row is analyzed by Fourier series expansion with emphasis on the existence of finite gaps at the driving points. The integral equations at the beginning are reduced to a series of linear simultaneous equations which contain only the Fourier coefficients of the electric currents of the same order. By appraising the current coefficients, the self-admittance is obtained as a sum of two parts: the finite series truncated at the number determined by the ratio of the circular-loop radius to the wire radius and the gap capacitance, and the mutual admittance is obtained as a finite series of fewer terms. Several computed curves concerning a parasitic endfire array of two elements are given, in which the computed values of the input admittance are substantiated by experiments, and radiation characteristics are examined to obtain a desirable configuration.