Research On Low Coupling MIMO Antenna Technology For Mobile Terminal

With the rapid development of wireless communication technology,the demand for the transmission rate and transmission reliability of the wireless communication is increasing.However,the scarcity of spectrum resources has brought some obstacles to the development of communication technology.The MIMO(Multiple-Input-Multiple-Output)technology can improve the transmission rate and spectrum utilization of the wireless signal better without increasing the transmission power and spectrum resources.However,with the increasing complexity of the electronic components and the increasing number of mobile phone screens,how to design a high isolation multiple antenna in the mobile terminal to ensure performance has become a design problem.The goal of this paper is to propose effective decoupling design for mobile phone terminals with different sizes.This paper first expounds the basic theory and design principle of the MIMO antenna,and introduces the channel capacity of the antenna system and the parameters of the envelope correlation coefficient of the multiple antenna system.Secondly,it introduces the different decoupling methods in the MIMO system,which lays the foundation for the follow-up work.With regard to the design of mobile terminal antenna,we first designed a multiple band MIMO cell antenna coated on a mobile phone frame,which includes GPS,Bluetooth and Wi Fi.Experimental and simulation results are basically consistent,and in the frequency band of VSWR ? 3,S11?-6 d B.The coating is integrated with the box in the cell phone and the box in the cell phone,which effectively saves the antenna space of the mobile phone.Then,by using the technology of loading and decoupling structure,we designed a mobile terminal MIMO antenna that can cover GPS1575,GSM1800,LTE2300 and WLAN2400 bands.And in the working frequencysection,the decoupling structure makes the S21 of the MIMO antenna less than-15 d B.The simulated and measured results show that the antenna has good performance.Finally,a high isolation MIMO mobile terminal antenna covering the GSM 1900,UMTS 2100 and Wi Fi 2400 band based on defect location(DGS)structure is proposed.The frequency range of S11?-6d B is 1780-2500 MHz,and the S21 of the antenna is less than-14 d B in the working band of the antenna;the isolation of the defective ground structure makes the isolation degree of the MIMO antenna higher than 6d B at least;the isolation of the antenna at the center frequency 2GHz is as high as-25dB.