Dual Polarized Broadband Antenna For The Fifth Generation Mobile Communication

As the key converter of guided electromagnetic wave and space electromagnetic wave,antenna plays an important role in communication system.In the past few years,as Internet plus industry is pushed by the country,the demand and quantity of communication users are increasing day by day,so the requirement of communication antenna development is also increasing.On the one hand,the coverage of the antenna should be as wide as possible to cover more communication user terminals,which requires the design of the antenna to ensure high gain and the coverage as wide as possible in the working wide bandwidth.On the other hand,due to the crowded spectrum resources in the low-frequency microwave band,people turn their attention to the millimeter wave band,which is more abundant.However,millimeter wave has the problem of large atmospheric absorption loss and short transmission distance,so people try to improve the antenna gain when designing millimeter wave antenna.In 2017,the Ministry of industry and information technology of China confirmed that 5G low-frequency band is 3.4-3.6GHz and 4.8-5.0GHz,millimeter wave band is 24.75-27.5GHz and 37-42.5GHz.In this paper,three kinds of antennas are designed:beam-width reconfigurable dual polarized antenna,millimeter wave dual linearly/circularly polarized antenna,and 3D printed antenna for 5G millimeter wave application.This paper first reviews the background and development of antenna research in 5G communication era,and a brief introduction of the research status at home and abroad,followed by the explanation of the theory of high-order mode resonator of magneto-electric dipole,and then focused on the detailed principle application and structure design of reconfigurable antenna,millimeter wave antenna and 3D printing antenna,as well as the simulation results analysis and experimental verification.The three antennas studied in this paper are as follows:The first design is a beamwidth reconfigurable antenna array with triple dual-polarized magneto-electric dipole elements is proposed for the base-station communication.By cutting off the arc-shaped corners on the radiating patches and employing the box-shaped reflector,a wide impedance bandwidth(SWR?2)of 78.4%with a peak gain about 12.3 dBi can be obtained over the 2G/3G/LTE/5G-C frequency band.Moreover,by introducing a two-stage tunable circuit composed of power dividers and a phase shifter,a widely adjustable beamwidth ranging from 24^o to 97^o in H-plane for port 1 and a beamwidth ranging from 22^o to100 ^o in E-plane for port 2 are achieved within the operating bandwidth,respectively.The second design is millimeter wave dual linearly/circularly polarized antenna.The two antennas designed are mainly designed for 5G millimeter wave communication frequency band.Here,a design method of broadband dual linearly polarized and dual circularly polarized patch antenna array driven by substrate integrated cavity is proposed.Firstly,a 2×2element dual linear-polarized antenna is designed,which is composed of a planer radiated patch,a shorted pin and a high-order-mode cavity.The high-order-mode cavity is excited by two grooves respectively to obtain two polarizations.The bandwidth of this subarray is over19.6%,covering the frequency range of 36.6-42.8 GHz.Then,an 8×8 element array antenna with two substrate integrated waveguide feed-networks is designed,which has a peak gain of25.8 dBi in the working band.The proposed antenna array has many advantages,such as wide bandwidth,low cross polarization level and symmetrical radiation mode.In this chapter,we design a dual polarized antenna with 2×2 and 8×8 elements fed by 45 degree rotating double arrow shaped patch,which is also fed by substrate integrated waveguide.The antenna has wide frequency bandwidth,axial ratio bandwidth and high gain.The third is a 3D printed antenna for 5G millimeter wave application.In order to improve the gain and reduce the transmission loss at the same time,the antenna is designed by combining a high-order mode resonator with a magneto-electric dipole.Secondly,the two 3D printed air-filled waveguide feed network with vertical placement can achieve high isolation at low cost.In addition,dual linear polarization(LP)and circular polarization(CP)antenna arrays are designed to obtain diversity polarization.In particular,low-loss full-corporate waveguide technology are studied for LP and CP operations.The measured bandwidth of 8×8dual line polarization antenna array is 13%(24.4-27.8 GHz)(S₁₁<-10 dB),the peak gain is28.3dBi,and the isolation is over 42dB;while the measured axial ratio bandwidth of 4×4 dual circle polarization array is 14%(24.6-28.3GHz),and the isolation is lower than 15dB.In addition,the high-order cavity structure of 3D printing has the advantages of low cost,small loss and flexible fabrication.