A Single-Port Multi-Band Horizontal Omni-directional Antenna

In this paper, a single-port multi-band horizontal omni-directional antenna for VHF/UHF band is proposed, which mainly consists of a sleeve dipole and an air-filled coaxial feeding network. The sleeve dipole achieves good radiation characteristics in the horizontal direction of the antenna in the designed four frequency bands. The gradual air-filled coaxial feeding network achieves better standing wave ratio characteristics in the designed four frequency bands. The antenna can reach voltage standing wave ratio less than 2.5 in the range of band f1:265MHz-305MHz, f2:560MHz-620MHz, f3:700MHz-860MHz, f4:980MHz-1045MHz. The ovality of the antenna in the horizontal direction is less than 0.5dB. The antenna operating bandwidth gain is greater than 1.2dBi, with a maximum gain of 5.9dBi. The measured results show that the antenna has good horizontal omnidirectional radiation characteristics in the designed four frequency bands, which is in good agreement with the simulation.