| In recent years,with the rapid development and application of wireless communication technology,the popularization rate of mobile terminal equipment has been gradually increasing,the mobile Internet has an explosive trend of development,the traditional time,frequency and spatial spectrum resources have not met the current wireless communication bandwidth requirements,how to effectively improve the system capacity and spectrum utilization is the key issue facing wireless communications.There are many technical means to achieve this goal,in which the orbital angular momentum(OAM)multiplexing technology,as a new type of multiplexing technology,has gradually become one of the hot topics in wireless communications.The OAM multiplexing technology utilizes the characteristics that the vortex electromagnetic waves carrying different OAM modal values are mutually orthogonal to each other,and can realize multiplex transmission of multiple vortex electromagnetic wave signals simultaneously and independently without interfering with each other on the same frequency,and which is an effective method for improving frequency spectrum utilization and system capacity.In this paper,while studying the basic theory of vortex electromagnetic wave,combined with a variety of technical means such as generation method of vortex electromagnetic wave,multiplexing technology,radiation principle and design theory of microstrip patch antenna,and design theory of array antenna,the rectangular microstrip patch antenna units are circumferentially equidistantly arranged with a certain radius to form an array antenna,adjacent patch units are made to have the same feeding phase difference through a feeding network,so that the array antenna generates and emits OAM vortex electromagnetic waves with a vortex structure.In this paper,ANSYSHFSS software is used to design two new 8-element OAM array antennas operating in two frequency bands,C band(5.4GHz)and X band(10GHz)respectively.In view of the current shortage of spectrum resources in wireless communication technology,this paper uses OAM array antenna to generate vortex electromagnetic waves with different modal values,and through the OAM multiplexing technology to achieve multiple signals multiplexing transmission at the same time and same frequency,to a certain extent,improve the spectrum utilization and communication system capacity.The new OAM array antenna designed in C band(5.4GHz)is mainly suitable for the most popular Wi-Fi frequency band and the upcoming 5G wireless communication technology,the X band(10GHz)new OAM array antenna is mainly used for space research,radio satellites,earth exploration satellites,meteorological satellites and other space exploration.From the S11 parameter,the VSWR,the Smith chart and the three-dimensional gain pattern of array antenna,we can know that the designed array antenna has better radiation performance and meets the basic requirements of OAM array antenna.And then use PADS9.5 software to draw array antenna PCB file map and produce array antenna PCB board,and then we use array antenna PCB board in communications systems for test analysis.At last,we summarize the whole paper and put forward the optimization scheme to the existing problems of the OAM array antenna designed in this paper,and the prospect of the OAM based on the array antenna is prospected. |
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