A Study of the e.m.f. Method

Abstract

The present work contains an investigation of the e.m.f. method to determine the input impedance of a thin biconical antenna as first suggested by Schelkunoff. By considering the various components of the currents flowing on the antenna, it has been shown that the sinusoidal part is, indeed, the dominating component among all these currents. An investigation of the total current at the end of the antenna, where the lateral surface of the cone and the spherical cap meet, shows that the current is not identically zero at that point, but vanishes as the reciprocal of the square of the characteristic impedance of the cone. The two approximate expressions of the complex conjugate power used in the e.m.f. method are derived, as well as the exact expression. Computation of some integrals occurring in the formulation is also treated in detail to show the various approximations involved.