Low-Profile and Wideband Surface-Wave Antenna of Conical Beam for UAV Applications

This letter proposes a low-profile and wideband conical-beam surface-wave antenna for unmanned aerial vehicle (UAV) applications. The compact antenna consists of a grounded dielectric conical frustum and a wideband feeding structure at its center. By using an inverted-cone feeding probe and a gear-shaped parasitic patch, cylindrical surface waves are excited to produce conical radiation patterns over an ultrawide frequency range. A prototype of the proposed antenna of only 6 mm thickness is designed, fabricated, and measured. The measured results demonstrate that the designed surface-wave antenna has an impedance bandwidth of 93.9% from 6.38 to 17.67 GHz with peak gains varying from 3.6 to 8.2 dBi and conical-beam radiation with low cross polarization. Due to its extremely low profile, wide bandwidth, and omnidirectional coverage, our proposed antenna can be potentially useful for communication and radar systems mounted on the surface of airplanes and UAVs.