The theory of top-loaded antennas: Integral equations for the currents

The general problem involving the distribution of current and the driving-point impedance of a top-loaded antenna is formulated. Consideration is given to an idealized structure having one or more cylindrical top-loading elements. For the practically important case involving conductors of small radius, the axial currents are obtained as the solution to a pair of coupled integral equations. Approximate solutions obtained by numerical methods for the inverted -, -, and four-element top-loaded antennas are compared with measured driving-point impedances. Satisfactory agreement indicates the possibility of utilizing the theory in the analysis of practical configurations involving many top-loading elements.