Spirapole antenna for communication systems utilizing both satellite and terrestrial assets

Abstract

In this paper an antenna is presented that satisfies the two-fold radiation pattern requirement of communication systems utilizing both geostationary satellites and terrestrial transponders for coverage of mobile terminal away from the equator. A typical requirement for such a system is a low profile antenna that maximizes left-hand circularly polarized radiation in the satellite viewing angle, from 30 to 70 from zenith, and vertically polarized radiation in the terrestrial station viewing angle, from 70 to 90 from zenith. This dual radiation pattern coverage is achieved by integrating a small four arm spiral with a top loaded monopole into a single compact volume, an antenna termed a spirapole.Index Terms-Direct broadcast satellite, dual pattern antenna, spiral, top loaded monopole.