Thin cylindrical antenna: variational solution with polynomial current approximation

All existing variational solutions to thin cylindrical antenna problems use two-term trial functions for currents, the form of which must either be based on some prior knowledge of current distribution along the antenna, or obtained by some other method. The present paper is aimed at eliminating these deficiencies in the applications of the variational method, by using as the trial function for current a polynomial of arbitrary order with complex coefficients. All the double integrals are transformed into sums of ordinary integrals to reduce computing time. The theory is applied to a number of isolated symmetrical cylindrical antennas of moderate lengths (up to approximately 2 ¿), starting with perfectly conducting dipoled ina vacuum, and ending with capacitively-loaded broadband cylindrical antennas. The theoretical results are in good agreement with available experimental data.