Characteristic mode synthesis of omni-directional radiation patterns for electrically small UAV

摘要

Structural antenna concept is attractive in low frequency platform antenna designs. Because the largest dimension of a UAV usually sits along the wings and fuselage, it is conventionally very challenging to achieve omnidirectional radiation patterns by using the UAV body as the radiator. In this paper, an approach is developed to synthesize an omni-directional radiation pattern using the characteristic modes of a UAV in UHF band. The synthesized pattern approximates well to the designated one, and the synthesized currents well explain the mechanism of the omni-directional radiation. The synthesized currents in turn give useful information on the design and placement of feeding structures for the excitation of the synthesized currents.