Input admittance and current distribution of infinitely long circular cylindrical antenna driven at center

In this paper, by change of integration path in complex spectrum domain and by defining input admittance as the ratio of complex radiated power to amplitude of square of voltage across the gap, new expressions of admittance (valid for all frequencies) of infinitely long cylindrical antenna with and without conducting ground are obtained. Meanwhile corresponding formulas of current distribution are derived in detail. Some numerical computations are also given.