Research On Dual-polarized Millimeter Wave Antenna Array In 5G Mobile Terminal

With the continuous development of economic society,people begin to expect the communication system to have lower delay,faster data transmission rate and higher stability,this leads to the birth of the fifth generation mobile communication technology(5G).Millimeter wave antenna is one of the core modules of 5G radio frequency system,and its performances determine the communication quality.However,the development of millimeter wave antenna technology has been limited by its inherent disadvantages such as large propagation loss,short transmission distance and weak anti-jamming ability.Meanwhile,the limited space of the mobile terminal also puts forward higher requirements on the size of antennas.In order to solve the above problems,this paper studies dual-polarized,wideband and high-gain millimeter wave antennas and arrays that can be used in 5G mobile terminal.A ±45° dual-polarized millimeter wave antenna array integrated on the frames of the mobile terminal is designed firstly based on the cavity-backed slot antenna.The antenna element consists of two ±45° orthogonally-placed bow-tie slots,a SIW resonator and GCPW.By optimizing the position and size of the bow-tie slot,a larger bandwidth and higher isolation can be obtained to achieve effective radiation.Then,four antenna elements are placed side by side to form a 1×4 linear array,and two such arrays are integrated on the longer frames to obtain a ±45° dual-polarized millimeter wave antenna array system that can be applied to the mobile terminal.The coverage efficiency of the antenna system is 52% when the threshold gain is 5d Bi,and it is less affected by the hand.In order to further expand the bandwidth,this paper designs another substrate integrated dielectric resonator antenna(SIDRA)on the basis.The antenna element achieves effective radiation through concentric air holes and metallized holes,and is fed by coupling slot.By exciting the hybrid mode of the dielectric resonator and coupling slot,the relative bandwidth of the proposed antenna reaches 16.1%.The dual polarizations are achieved by exciting two orthogonal modes,with an isolation of 40 d B between the two ports.Two 1×4 linear arrays are integrated on the longer frames of the mobile terminal.The coverage efficiency of the antenna array is 80% when the threshold gain is 5 d Bi,and is less affected by the one-hand and twohand data modes.In addition,the research also places the sub-6GHz low-frequency antenna on the short frame of the mobile terminal,and the antenna system can cover 5G millimeter wave frequency band and low frequency band simultaneously without adding any structure.The two millimeter-wave antenna arrays designed in this research have the characteristics of dual polarizations,high gain,high coverage efficiency and easy integration with mobile terminal's frames,so they have great potential in the future application.