Research On Ultra-Short-Wave Broadband Omnidirectional Antenna Technology

With the development of communication technology,in order to meet the needs of wireless communication,the ultra-short-wave omnidirectional antenna needs to have the advantages of broadband and small size.In this paper,combined with scientific research topics,the broadband and miniaturization technology of omnidirectional dipole antenna is deeply studied,and its matching technology is discussed.The research work is mainly divided into three parts:1.Research on ultra-short-wave broadband omnidirectional airborne antennas,focusing on the miniaturization and broadbandization measures of monopole antennas.Firstly,on the basis of the traditional monopole antenna,the form of the monopole antenna is improved,the branch and coupling feed structure are introduced,and the top loading,lumped element loading and impedance matching circuit are studied,and several measures are verified.Finally,the monopole antenna can achieve a VSWR of less than 2 in the target frequency band,the size of the antenna is 0.18λ_L×0.08λ_L,and the horizontal plane has good omnidirectionality.The measured results are consistent with the simulation results.2.Research on the ultra-short-wave broadband omnidirectional array antenna,focusing on the improvement of the miniaturization of the array unit and the research on the power division network,and design two broadband printed array antennas working in the ultra-short-wave frequency band.Firstly,based on the branch-coupled broadband printed dipole antenna,through the analysis of the current on the antenna,slotting measure is taken to provide space for the network design without changing the electrical performance of the antenna.And choose the appropriate unit spacing,the feeding network is studied and designed.The array antenna is finally within 40%of the bandwidth,and the lateral size is0.07_Lλ.The second array antenna is a printed dipole antenna based on balun coupling.Its slot line is improved to reduce the size of the antenna.The influence of the antenna arrangement on its omnidirectionality is mainly studied.The final designed array antenna can Within the relative bandwidth of 35%,and the horizontal plane of the full frequency band has good omnidirectionality,the lateral dimension is 0.13λ_L,the measured results are basically consistent with the simulation results.3.Research on the ultra-short-wave horizontally polarized omnidirectional antenna,designed a horizontally polarized omnidirectional combined loop antenna,focusing on the miniaturization of the loop antenna unit and the multi-section impedance matching technology of the combined loop antenna,realizing the antenna broadband Finally,the antenna is within the relative bandwidth of 12%,the antenna size is 0.3λ_L×0.3λ_L×0.12λ_L,the gain in the full frequency band meets the index requirements,and the horizontal plane has good omnidirectionality.