HELICAL ANTENNAS FOR HIGH POWERED RF

Radiating high power RF below 1 GHz can be difficult. Large structures are preferred for high voltage operation; however, large structures are difficult to deploy. Conversely, small geometries are more easily deployed, but insulating the high voltage can be difficult. Dipole structures have made their way into use due to the relatively simple and compact implementation; however, their radiation pattern is not desirable, since they radiate in a donut pattern, which can disrupt, or even destroy one's own electronic controls. Impulse Radiating Antennas have been configured for wideband operation; however, their large geometry is very difficult to deploy. Helical antennas offer many advantages over other methods. The helical antenna is relatively compact, with its cylindrical geometry. The antenna's geometry is wavelength dependent, but is acceptable from several hundred MHz and higher, with the upper limit being dominated by the high voltage operation. It offers a good gain factor and can be operated as a narrow band, or wide band device. Applied Physical Electronics, L.C. has been developing high voltage helical antennas for narrow band and wide band applications. This paper describes the fundamental operation of a 400 MHz helical antenna driven by Marx generators. Simulation and experimental results are provided.