Millimeter-Wave Multibeam Antennas For Terminal Application

In recent years,with the rapid development of communication field,the number of wireless communication users has increased dramatically,and the spectrum resources have become more and more scarce.Millimeter wave band has attracted more and more researchers and scholars'attention because of its extremely rich spectrum resources.Considering the high transmission loss and various other system requirements in millimeter wave frequency,the substrate integrated waveguide?SIW?has the advantages of low profile,low insertion loss,light weight,easy to integrate planar circuits and so on,which is widely used in millimeter wave applications.In this paper,the terminal millimeter wave multibeam antenna is studiedFirstly,the basic theories of antenna array,electromagnetic wave polarization characteristics,multi-beam scanning principle,SIW,substrate integrated E-plane waveguide?SIEW?are briefly summarized,which are the theoretical basis of all designs in this paper.A two-dimensional scanning multi beam antenna is designed to realize the two-dimensional scanning of 4×4 beams.In this design,a new compact two-dimensional Butler matrix with common structure of H-E plane is proposed.The two-dimensional Butler matrix is composed of two groups of 4×4 Butler matrices which are orthogonal to H plane and E plane.The difficulty in this design is to realize the design of plane E-plane4×4 Butler matrix by sharing the common wide edge of the four layer H-plane 4×4 Butler matrix.By reconstructing the components of H-plane and E-plane Butler matrix,the components of two-dimensional Butler matrix?eight port coupler,eight port cross coupler and two-dimensional phase shifter?are designed,and two-dimensional is realized conveniently by using these components The design of Butler matrix.Then,based on the newly proposed two-dimensional Butler matrix,a 4×4 stepped array and a transition network connecting the two-dimensional Butler matrix and the 4×4 stepped array are designed,and a compact two-dimensional multibeam array is designed.The two-dimensional scanning of 4×4 beam is realized.Compared with the one-dimensional scanning antenna,the two-dimensional scanning antenna has higher flexibility.A dual-polarization multibeam antenna is designed.TE₁₀ mode transmission is supported in SIW and TE₀₁ mode transmission is supported in SIEW.Therefore,a multi-layer dual polarization antenna unit based on SIW and SIEW is proposed in the design and applied to linear array.The feed network of the multibeam antenna uses a single-layer H-plane 4×4 Butler matrix.In order to connect the feed network and the antenna array conveniently,a mode converter and a single-layer to multi-layer transmission line are designed.Compared with single polarization multi beam antenna,dual polarization multi beam antenna can improve the system capacity.