| The rapid development of wireless communication technology makes 5G mobile communication coming into our daily life.It is thought that the sub-6GHz band serves as the primary frequency band for the introduction of the 5G,providing an optimal balance between coverage and capacity,especially for the N77(3.3 GHz-4.2 GHz),N78(3.3 GHz-3.8 GHz)and N79(4.4 GHz-5.0 GHz)bands.How to design a base station antenna with stable radiation performance in this frequency band becomes a challenge that needs to be solved urgently.As a potential candidate of the base station antenna,magnetoelectric dipole antenna has attracted attention because of its boradband and good radiation characteristics.Besides,dual-polarization technology which can improve spectrum utilization effectively can also be applied to magneto-electric dipole antenna.MIMO antenna array is the trend of antenna development in the 5G era as a result of the high system capacity without increasing the transmission power.This work fouses on the requirement of base station antenna in 5G era,and designs boardband/dual-band dual-polarization magneto-electric dipole antenna in Sub-6 GHz frequency band,also a MIMO antenna array is proposed.Concents of this thesis include:Firstly,the history of wireless communication systems and the current status of base station antennas and MIMO antenna arrays are introduced,and the principles of electric dipole,magnetic dipole,complementary antenna and MIMO antenna array are reviewed.Secondly,based on the theory of the magneto-electric dipole antenna that fed by ?-shaped probe,the influence of magneto-electric dipole antenna on its half power beam width is discussed,and a magneto-electric dipole antenna consisted of fishtail-shaped dipoles and vertically oriented shorted patches is designed.The antenna works in the N77 and N78 frequency bands with good impedance matching of SWR ? 1.5.The radiation characteristics are stable,and the beam widths in E-and H-plane are well controlled.Thirdly,based on the wideband magneto-electric dipole antennas operation in the N77 and N78 frequency bands mentioned above,a W-shaped slot-loaded dual-band dualpolarization magneto-electric dipole antenna is designed.In addition,the ?-shaped probe and the reflector are improved to correct the radiation pattern distortion at the higher frequency band.Finally,a 25-element diamond-shaped MIMO antenna array is designed using a broadband magneto-electric dipole antenna operation in the N77 / N78 frequency band as a unit.The elements in the array are verified to be uncorrelated with each other,which can meet the requirements of MIMO antenna arrays. |
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