Low-Profile, Tri-Band, Horizontally Polarized Omnidirectional Near-Field Resonant Parasitic Antenna for UAV Applications

A low-profile, tri-band, horizontally polarized (HP) omnidirectional near-field resonant parasitic (NFRP) antenna is designed in this paper. The NFRP antenna consists of four parasitic arc dipoles and a pair of drivers, and the far-field radiation field is combined into a horizontal omnidirectional radiation pattern. The tri-band antenna operates in the half-wavelength current distribution mode of the arc dipole for the lower band, while it works in the full-wavelength current mode for the middle band. For the upper band, a new resonance is excited by loading the arc branches. The simulation results show that the NFRP antenna covers 840.5-845 MHz, 1430-1444 MHz and 2408-2440 MHz of the three UAV communication bands in China, with the lateral size is 0.37λ
0
, the profile size is less than 0.01λ
0
, and has good omnidirectional performance.