| Under the 5G communication layout,all communication systems use sub-6GHz frequency bands,which caused congestion in the low-frequency spectrum,and the frequency band of 5G mobile communication has leapt to high frequency.So Millimeter wave has become a research hotspot due to its rich spectrum resources,and the deployment of 5G millimeterwave in China,the U.S.and Europe has been put on the agenda recently.Substrate integrated waveguide(SIW)is often used for the transmission of high frequency because of its advantages of low loss,small size,ease of integration.This thesis addresses the disadvantages of millimeter-wave transmission with large communication transmission loss,susceptibility to water and oxygen absorption,and reduced signal coverage after increasing gain.Broadband high-gain SIW millimeter-wave antenna that meets the requirements of "Global Communications" and multi-beam antenna that realizes spatial scanning have been investigated separately in this thesis.The main research contents carried out in this thesis are as follows:Firstly,in order to deal with the defect of high transmission loss in millimeter-wave communication,a SIW slot coupling microstrip patch antenna is designed in this thesis.The peak gain of antenna has been originally increased to 7.9 d Bi by a radiation method in which a microstrip patch and an SIW slot for coupling feeding were placed orthogonally.Based on this structure,different parts of the microstrip patch were excited by using the composite loading mode of the parasitic patch and the short-circuit metal via hole,which added a new resonance mode,expanded the bandwidth by 11.77% and increased the peak gain by 0.6d B.Through simulation,the antenna could finally achieve a peak gain of 8.50 d Bi,a relative bandwidth of 23.17%,and it could cover 24.75 GHz to 27.5 GHz in China,27.5 GHz to 28.35 GHz in the United States,and 24.25 GHz to 27.5 GHz in Europe simultaneously,which achieved the broadband performance required by "Global Communications" and high-gain performance.Then,in order to solve the problem that the single antenna cannot meet the higher gain requirements in terminal applications,a four-way power divider network has been designed for the array,which cascaded two sets of two-way power divider networks designed successively in this thesis.And the output of all ports has equal amplitude and equal phase.The design of high gain array is achieved after combining the power divider network with the antenna.Through simulation,the array finally realized the peak gain of 13.21 d Bi,which was 4.71 d B higher than the single antenna,but the half-power beam width was ±10°,which means that the beam width was compressed.Finally,in order to solve the problem that the signal coverage decreases with the increase of the gain,the double-layer 4 ?4 Butler matrix beamforming network designed from the single-aperture and the double-aperture cross coupler were designed successively in this thesis.The beamforming network realized energy transmission between double layers by means of slot coupling,which reduced the size by 50% and could be suitable for more application scenarios with volume limitation.After comparative analysis,the double-layer Butler matrix feed network based on a double-aperture cross coupler with a smaller phase output error(±10°)at each port was selected to complete the design of the multi-beam antenna.Through simulation,the antenna finally realized that the peak gain fluctuated within the range of 9.26 d Bi ~11.23 d Bi and the scanning angle covered 89.75°,which increased the range of signal coverage and realized spatial scanning while achieving high gain performance. |
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