High Power VLF Transmitting Antennas Using Fast Wave Horizontal Dipole Arrays

摘要

Horizontal VLF transmitting dipole arrays are much easier and less expensive to construct than vertical VLF transmitting antennas in use at the present time. The horizontal dipoles have much greater power-radiating capability and bandwidth. The theoretical and experimental effects of mutual resistance on array efficiency gain over one dipole are presented. The radiation efficiency is greatly increased by increasing the wave velocity along the resonant dipole. Radiation characteristics of a theoretical 18-dipole array on Hawaiian lava are shown. The antenna radiation pattern needed at VLF in order to get omnidirectional coverage is presented. Directivity is needed due to the non-reciprocal east-west propagation attenuation. (Author)