Millimeter Wave Multi-beam Antenna Based On LTCC

With the rapid development of mobile communication technology,there is not enough bandwidth in the low frequency band.Millimeter wave has become a research hotspot with the advantages of wider bandwidth and higher transmission rate.Low temperature co fired ceramic(LTCC)can highly integrate multiple devices into multilayer dielectric board,which meets the design requirements of high precision and miniaturization of millimeter wave electronic products,The substrate integrated waveguide(SIW)fabricated by LTCC technology has been widely used to solve the problems of high loss of microstrip transmission line in millimeter wave band and large volume of traditional dielectric waveguide.This paper is based on the above background,the main content can be summarized as follows:Firstly,the research status of LTCC millimeter wave multi beam array antenna at home and abroad is introduced,and the design principle and design steps of SIW transmission structure,the process characteristics and processing flow of LTCC and the principle of multi beam scanning array antenna are given,which lays a theoretical foundation for the subsequent design work.Then,a miniaturized one-dimensional millimeter wave multi beam array antenna is designed based on LTCC technology.A design method of eliminating the additional phase difference introduced by even fold is introduced.The double layer 8 × 8 Butler matrix designed based on 3d B directional coupler of E-plane is folded twice,and the overall size is reduced by more than 50%.The folded Butler matrix is cascaded with a 1 × 8 linearly and uniformly distributed multilayer parasitic patch array antenna,and eight scanning beams are realized with a beam coverage angle of ± 58 degrees.Finally,a miniaturized two-dimensional millimeter wave multi beam array antenna is designed based on LTCC technology.In the design,a 2 × 4 uniform array composed of multilayer parasitic patch antenna elements is proposed.The feed network of the array antenna consists of two groups of miniaturized 4 × 4 Butler matrices and four H-plane3 d B directional couplers.The size of 4 × 4 Butler matrix is reduced by more than 50%compared with the traditional single-layer design.Because the input ports are respectively located in two layers of dielectric plates,the four directional couplers in the twodimensional beamforming network can be completely integrated under the antenna array,thus realizing the overall miniaturization design of the two-dimensional millimeter wave multi beam array antenna.The antenna can scan 8 beams in half space in two dimensions,and the antenna beam gain is more than 10.8d Bi.Compared with one-dimensional beam scanning,two-dimensional scanning can achieve more flexible beam changes and higher beam resolution.