Novel Dual-Beam And Wide-Scanning Array Antennas Investigations For 5G Application

For the 5G wireless communication systems,the internet of everything(Io E)is the core application,covering all aspects of smart city,autonomous driving,smart home and internet of thing.With the rapid expansion of the number of terminal accesses and data throughput,modern array antennas are facing new requirements and challenges,and the researches mainly focus on multi-beam,multi-band,broadband,wide-scanning and highefficiency ability.Aiming at high-performance arrays for 5G mobile applications,combined with novel antenna types and packaging technology,in-depth research in the microwave and millimeter wave frequency bands for expanding beam diversity and enhancing the isolation have been carried out.The main contents of this thesis are summarized as follows:1.Novel dual-beam metasurface antennas(MSAs)based on multi-phase degrees of freedom method: firstly,based on the single-phase degree of freedom method,a tavelling-wave network with adjustable magnitude and phase is proposed.Combined with the novel metasurface antenna,a dual-beam MIMO antenna with low sidelobe and high gain is designed.Furtherly,a novel feeding network with dual-phase degrees of freedom is proposed and realize independent beam control of dual bands,which is applied in dual-band dual-beam MSAs.Compared with the traditional antenna array,the proposed MSAs have the advantages of flexible beam controllability,low profile,compact structure,etc.,which provide a good design protype for the spatial diversity MIMO antenna in 5G wireless co mmunication.2.MSAs with stable beam angle based on positive phase response method: A novel method for stable beam angle that uses the equivalent circuit of antenna to achieve positive phase response is proposed.The connection between the equivalent circuit and MSA element is studied.Based on this method,the narrowband ±45° dual-polarized metasurface antenna array and the broadband metasurface antenna array are designed.These MSAs based on positive phase response method solve the frequency-scanning problem,which has potential application in wireless communication scenarios with stable coverage.3.Millimeter-wave phased array in advanced package based on planar couplingoffset path method: A planar decoupling method introducing an extra coupling cancellation path is proposed for large-scale phased array.By optimizing the size of the decoupling stubs,the magnitude and phase of the introduced coupling path are adjusted to cancle the inherent coupling.Based on the method,4×4 phased arrays using LTCC and HDI packaging technology are designed,featuring broadband decoupling,improved radiation efficiency and wide-angle scanning.This planar coupling-offset path has been successfully applied to design wide-angle scanning and high-efficiency millimeter-wave antennas in package.4.Dual-polarized millimeter-wave phased array antenna based on spatial coupling conversion method: A decoupling method of spatially polarization rotation is proposed,which converts the coupling of cross-polarization into coupling of the co-polarizations.Based on the LTCC packaging technology,the proposed decoupling method applied in ± 45°dual-polarized phased array is used to achieve high isolation of co-polarization and crosspolarization at the same time,so that radiation efficiency and wide-angle scanning range can be improved.This decoupling method can solve the problem of unconventional multidimensional dual-polarization coupling and provides a good solution for the decoupling of5 G millimeter wave dual-polarized package antennas.