Design of VHF Horizontal Polarization Omnidirectional Antenna

Horizontally-polarized antennas are usually used in the system of polarization diversity to improve the performance of communication chain and its reliability. Furthermore, the bandwidth of the antenna openly governs the rates of data communication. In order to meet the engineering requirements of high rates for data transmission and multi-band communication, the antenna bandwidth of the communication system needs to be further increased. In this paper we present the scheme of an omnidirectional loop antenna for horizontally-polarized systems. The research status of the horizontally-polarized omnidirectional antenna, and the working principle and radiation characteristics of the small loop antenna are elaborated in detail. The field expression of the loop antenna is deduced from the wave equation, and the characteristics of the far-field and the near-field of the loop antenna are analyzed. On the basis of theoretical analysis, a practical loop antenna is researched and developed for the demands of wireless communication engineering applications. Moreover, we present the related loop antenna technology and how to implement it. The radiation pattern of the antenna is obtained through computer simulations. Our empirical results show that the small loop antenna based on capacitive loading can realize the radiation characteristics of the horizontal polarization omnidirectional pattern. The small loop antenna has the advantages of small size and easy portability, and the small loop antenna operating in the resonant state has a high Q value, which gives it better frequency selectivity. The design and research of this paper have important reference significance for the engineering design and application of the VHF band horizontally-polarized omnidirectional antenna.