Analysis of hula-hoop antenna and consideration of its radiation resistance

The current distribution of the "hula-hoop" antenna is studied and its radiation resistance is considered. It is analyzed by being decomposed into an unbalanced-driven type and a balanced-driven type, on the assumption that the ground is a perfect conductor. Since the balanced type already has been analyzed, this paper is devoted to the unbalanced type, which is called a ring antenna. We present calculated and measured current distributions, and show that the calculated values of the radiation resistance are near
21(2kc)^{2}
(
kc
: electrical length of the distance between the antenna and ground) which agree with those calculated by the Poynting vector method.