Design of a Multi-Section Omnidirectional High-Gain Base Station Antenna

High-gain omnidirectional antennas are widely used in outdoor emergency communication systems. This paper presents a multi-section omnidirectional high-gain base station antenna based on coaxial colinear (COCO) structure. It operates within the UHF band and has an overall length of less than 5.4m. The antenna is divided into three sections to improve portability, in which each coaxial unit uses air coaxial transmission, compared with dielectric coaxial, the use of air coaxial transmission can significantly reduce the number of antenna oscillators, at the same time significantly improve the radiation efficiency of the antenna. Due to the use of air coaxial, the impedance is relatively large, for this reason, the design of specific impedance sectionalizer can realize impedance mutation to achieve the specifications required. Test results show that the gain is greater than 9dBi in the operating band and the VSWR is less than 1.5, and good horizontal omnidirectionality in the working band, which is consistent with the simulation results.