Research And Design Of Broadband Dual-Polarized Base Station Antenna

With the rapid development of 5G communication frequency bands,high-quality,high-speed,and large-capacity communication signals are required,so it also poses higher and higher challenges for base station antennas.Nowadays,base station antennas are also constantly developing in the direction of multi-function,such as miniaturization,broadband,multi-frequency,filtering and so on.This thesis mainly focuses on broadband dual-polarized base station antennas,and conducts research in the directions of miniaturization,filtering,and MIMO arrays.The specific research contents are as follows:Firstly,a broadband dual-polarized low-profile base station antenna is proposed,and its operating frequency band covers 2G,3G,and 4G LTE communication frequency bands.By loading the parasitic ring,a new resonance point is generated at high frequency,and the newly generated resonance mode merges with the resonance mode of the antenna itself,thereby broadening the working frequency band of the antenna.At the same time,the AMC reflective surface is loaded to reduce the height of the antenna’s vertical plane and realize the miniaturization function.Finally,the designed antenna achieves an impedance matching bandwidth of 48.5%（1.73GHz-2.84GHz,VSWR<1.5）,the port isolation is higher than 25d B,the in-band gain is above 8.5d Bi,and the profile height is reduced to 24mm（0.176λ₀）,which greatly saves the space occupied by the antenna compared to a quarter wavelength of the height of the antenna profile of the traditional base station.The designed antenna operating frequency band covers 2G（GSM1800/1900）,3G（CDMA2000,WCDMA,TD-SCDMA）and 4G LTE communication frequency bands,and has practical application value in engineering.Secondly,a broadband dual-polarization filter base station antenna for 5G communication frequency band is designed.Loading a parasitic inner loop on a traditional loop dipole antenna can generate a radiation null at high frequency to achieve filtering performance.In addition,a new resonance point will be generated at high frequency.By adjusting the newly generated resonance point to achieve impedance matching,thereby broadening the antenna bandwidth.At the same time,a large parasitic ring is loaded on the back of the dielectric substrate,thereby generating a radiation null at low frequencies to achieve filtering performance.Finally,the designed antenna achieves an impedance matching bandwidth of48.3%（3.3GHz-5.4GHz,VSWR<1.5）,and the average gain is above 8d Bi.The low frequency（2-2.7GHz）out-of-band rejection is greater than 27d B,and the high-frequency（6.1-6.5GHz）out-of-band rejection is greater than 17d B.The HPBW is within the range of66°±2.1°,and the measured efficiency is about 85%.In addition,the designed antenna works in the 5G working frequency band below Sub-6G,and has good impedance matching,which can be used in 5G base station antennas.Finally,a broadband dual-polarization MIMO base station array antenna for the future communication working frequency band,that is,the 6GHz-8GHz frequency band,is proposed.First,a miniaturized broadband dual-polarized base station antenna unit is proposed,and its aperture surface size can be reduced to 0.3λ,and then a compact staggered arrangement is used to form an array,which can place more antenna units in a limited plane space,and then designed three decoupling structures,frequency selective surface,decoupling metal surface DMS and decoupling cladding.Finally,the three decoupling structures are combined together,combined with a one-point three-power divider,and the2×3,4×3,2×6 scale arrays are respectively formed,and the VSWR<2.Both the co-polar and hetero-polar coupling of the port are below-20d B.Finally,a larger-scale 12×10 MIMO array base station antenna was processed and tested,and the feasibility of the designed structure was verified,which can be applied in the future communication frequency band ultra-large-scale MIMO array base station antenna.