Current on and input impedance of a cylindrical antenna

Abstract

The electric current on a finite antenna is expressed as the sum of a currcnt emanating from the gap and two currents rellected from the ends. These currents are determined for a per~ectly conducting hollow .pipe o~ circu lar-cross section. The antenna is excited by an electnc fi eld parallel to the aX Is applied across a gap of finite width which encirclcs the antenna. The currents are a lso determined for a thin antenna of any cross section . From thc results the current on and the input admittance of the antennas are determined. It is shown that the thin antenna theory yields an incorrect result for the admittance because it ignores a boundary layer effeet near the gap.