The Thick Tubular Transmitting Antenna

The growing importance of electrically thick monopole antennas has suggested a re‐examination of the model used in the derivation of the integral equation for the current in tubular antennas. It is shown that when such an antenna is driven from a coaxial line in the usual manner, which maintains a field along a narrow circumferential region on the outside surface of the tube (instead of along both the inner and outer surfaces), an additional term is required in the integral equation. This is negligible when the antenna is electrically thin, but of major importance when it is not. A quantitative comparison of conductances is provided over a wide range of thickness.