Research And Design Of Omnidirectional High Gain Antenna

With the development of wireless communication technology,omnidirectional high gain antenna,because of its good horizontal omnidirectional radiation characteristics,is very suitable for the application requirements of airport tower,relay station,Ground-based Navigation System and so on,which makes it attracted more attention in the increasingly complex electromagnetic environment.This paper elaborates the research background and significance of omnidirectional high gain array antenna and its current development status.According to the actual needs of the research project,the broadband and low sidelobe technology of omnidirectional high gain antenna is studied.The main research content are as follows:1.Design of X-band omnidirectional biconical array antenna.When the working frequency of the series feed array deviates from the center frequency,the maximum radiation direction of the antenna will deviate from the normal direction of the array.This paper analyzes the radiation mechanism from the perspective of equivalent circuit and proposes the technology of feeding omni-directional radiation biconical array with a coaxial line with a slot in the middle.The circular coupling slot is cut in the middle to feed the waveguide structure surrounded by outer conductor and biconical,and then the antenna element is excited to form omni-directional radiation.To further reduce the sidelobe level of the antenna,a short circuit structure is added at both ends of the waveguide structure.Finally,the results show that the designed antenna has stable E-plane radiation pattern and achieves omnidirectional radiation with 8d Bi gain in 11.1% impedance bandwidth.2.Ku band omnidirectional circular waveguide slot antenna design.In view of the relatively high sidelobe level of traditional omnidirectional circular waveguide slot antennas,the Doyle-Chebyshev synthesis method is proposed to perform comprehensive analysis on circular waveguide slot antennas.Considering the influence of coupling,the sidelobe level of the antenna is reduced by adjusting the slot distribution;the cross-polarization suppression technology of the inclined slot antenna is further studied,and the cross-polarization is suppressed by loading circular parallel diaphragms.The results show that the main polarization sidelobe level of the antenna is reduced to-20 d B by optimizing the slot inclination angle according to the Doyle-Chebyshev synthesis method,and the cross polarization of the antenna is significantly reduced.Compared with the traditional omni-directional waveguide slot antenna,the sidelobe level of the H-plane synthetic pattern is also reduced by 7.5d B.