Research On Decoupling Technology Of C-band Cell Phone MIMO Antenna

With the commercialization of the 5G communication era in November 2019,the wireless communication network system technology related to 5G has entered a stage of rapid development.The technical advantages of broadband coverage such as reliability,etc.,also have the significant advantages of widening limited spectrum resources,and it is necessary to continuously introduce new technologies in the case of very limited antenna design space,so as to better Improve the current channel data capacity,space utilization efficiency,high frequency spectrum utilization efficiency and energy utilization efficiency.Because of this,it also leads to some problems that are difficult to solve by many traditional technical means.5G wireless communication requires a large number of MIMO(Multiple-Input Multiple-Output,multiple-input multiple-output)antennas and requires a wide enough frequency band,and the development of smart phones is becoming thinner and more comprehensive,so that the limited space of terminal equipment needs to accommodate More antenna units and more antennas close to each other will produce a strong electromagnetic coupling effect,which will seriously affect the original radiation characteristics of the antenna unit,thereby affecting the performance of the antenna.Therefore,how to realize the miniaturization of the antenna occupied space,high isolation,and larger bandwidth requirements in a very limited space,and how to explore the optimal layout of different antenna arrays are the problems that need to be solved urgently for MIMO antennas of smartphones.In this paper,three aspects of research are carried out: a decoupling method of odd-even mode impedance compensation is proposed to verify the simplification and miniaturization of the decoupling structure design of the symmetric antenna while achieving high isolation;Decoupling design to solve the problem of decoupling between new antenna layouts;a self-decoupling design for miniaturized multi-mode terminal ultra-wideband antennas is proposed to comprehensively improve the space utilization of MIMO antennas and greatly expand the bandwidth of MIMO antennas Isolation is also achieved.The specific work content is as follows:1.First,according to the deduced principle,a decoupling method for odd-even mode impedance compensation is proposed.In order to compensate for the change of the odd-even mode input impedance due to coupling,according to the structure of the symmetric MIMO antenna with different structure types,according to the circuit characteristics of the odd-even mode excitation,the most simplified and effective structure is designed to realize the compensation of the odd-even mode input impedance to This achieves simultaneous matching and decoupling of the coupled MIMO antenna.In this chapter,the design of the decoupling structure of the two antenna structures is analyzed respectively,and the decoupling is finally realized by two forms of independent compensation of common-mode input impedance and independent compensation of odd-mode input impedance,and the proposed principle is completed.correctness verification.2.It is proposed to design a U-shaped antenna monopole with an equal length of the monopole structure to form a horizontal opening,so as to achieve the purpose of miniaturization of the antenna unit,and then through parallel movement,the physical distance between the antennas is only 1mm,forming The asymmetric compact MIMO mobile phone antenna,combined with the effective analysis of the change of the self-input impedance of the two asymmetric antennas and the distribution of the radiation current characteristics,proposes a decoupling design for the asymmetric MIMO mobile phone antenna pair,and further designs and implements six elements Asymmetric antenna design with decoupling.3.A miniaturized ultra-broadband antenna with four resonant frequency points is proposed and designed.Each part achieves miniaturization and ultra-broadband through the design of progressive parasitic coupling and bending,and then symmetrically placed about the central symmetry plane.The self-decoupling in the ultra-wideband is formed,and the design of the self-isolated ultra-wideband four-frequency MIMO antenna is completed.