Research On High Isolation Broadband 5G MIMO Mobile Phone Antenna

With the continuous development of mobile communication technology,mobile phones have become an indispensable part of people’s production and life in modern society.In the 5G era,in order to meet the communication needs,mobile phone antennas need to cover multiple 5G working frequency bands.In addition,the miniaturization of mobile terminal equipment and the wide use of Multiple-Input Multiple-Output(MIMO)technology make the isolation performance of MIMO antenna in mobile phones particularly important.This paper focuses on the design of broadband and high isolation of MIMO mobile phone antenna,and the specific work includes the following three aspects:(1)A compact high isolation broadband MIMO mobile phone antenna is designed.Two antenna elements are integrated into an antenna pair through a common coupling grounding branch,and the two antenna pairs form a four-element MIMO mobile phone antenna.The antenna broadens the bandwidth by opening a slot in the radiation patch,and the common coupling ground branch not only participates in radiation,but also acts as a decoupling branch.The working frequency band of the antenna is 3.4～6.5GHz,the isolation is better than 15dB,the efficiency is more than 42%,and the Envelope Correlation Coefficient(ECC)is less than 0.25.which meets the design requirements of mobile phone antenna.In addition,the antenna does not introduce additional decoupling structure,giving consideration to a wider working frequency band and high isolation,and the antenna pair has the advantages of compact structure and low profile.(2)A miniaturized and highly isolated broadband MIMO mobile phone antenna is designed.A broadband antenna element is designed,and based on this,a four-element MIMO antenna and an eight-element MIMO antenna are proposed.The four-element MIMO antenna realizes self-decoupling by the grounding branch in the antenna element’s own structure.The working frequency band of the antenna is 3.2～6.6 GHz,the isolation is better than 15.5 dB,the efficiency is more than 52%,and the ECC is less than 0.05.Eight-element MIMO antenna relies on its own structure and the reasonable layout of antenna elements to decouple.Its working frequency band is 3.4～6.1GHz,and its isolation is better than 15 dB,efficiency is higher than 45%,and ECC is less than 0.1.Both antennas take into account the requirements of size,bandwidth and isolation,and have self-decoupling characteristics,simple structure and good practical value.(3)A high isolation broadband MIMO mobile phone antenna loaded with metal frame is designed.Firstly,a broadband antenna element loaded with metal frames is designed,and a"mountain" decoupling structure is introduced between the two antenna elements to form a twoelement MIMO mobile phone antenna.Secondly,four two-element MIMO mobile phone antennas are placed on the four metal frames of the mobile phone by using the principle of polarization diversity of vertically placed antenna elements,and an eight-element MIMO mobile phone antenna loaded with metal frames is proposed.The working frequency band of the antenna is 3.3～7.1 GHz,the isolation in the working frequency band is better than 15 dB,the efficiency is higher than 54%,and the ECC is less than 0.25,which meets the design requirements of the mobile terminal antenna.The antenna has good broadband,high isolation and other characteristics,and has good application value in 5G mobile terminal equipment loaded with metal frame.The three high isolation broadband MIMO mobile phone antennas proposed in this paper provide more ideas for the application of MIMO antennas on mobile phones in the 5G era,and have certain reference value.