Miniaturization Technology Of TD-LTE Base Station Antenna

With the rapid development of mobile communication network,people put forward higher requirements on the performance of the base station antenna.Base station antenna is developing towards wideband,miniaturization and integration.Base station antenna with broadband and miniaturized has a wide range of applications because of its small size,reduced installation difficulty,wide bandwidth,light weight,easy to beautify or conceal such great advantages.This thesis mainly studies the broadband and miniaturization technology of TD-LTE base station antenna.The main content of this thesis is summarized as follows:1.Two kinds of base station antenna elements are proposed with broadband and dual polarized.a)Folded dipole antenna that is coupling fed by an L-shaped microstrip line.The bandwidth of the antenna is widened by coupling feed.Simulation results show that the bandwidth of the antenna is 1.88GHz-2.9GHz(42.7%),the antenna gain is above 7d Bi,and has good isolation(> 35 d B).Two folded dipole antennas are placed orthogonally,the antenna element can achieve ± 45 ° dual polarization mode.b)The bowtie dipole antenna with parasitic element.By loading the parasitic element and the metal back cavity,under the requirement of VSWR <1.5,the antenna bandwidth is 1.70GHz-3.84GHz(77.3%)and the port isolation is greater than 31 d B.The bowtie dipole antenna is fabricated and tested.The measurement gain is higher than 8.5 d Bi and the cross polarization is higher than 25 d B in the entire operating band(1.71GHz-2.7GHz).2.Antenna array with 10 elements is designed based on the folded dipole antenna.The design method of array antenna is studied.The use of partial coupling between the elements to reduce the unit spacing,compared to the original antenna array length reduced by 42%.The test results show that the maximum gain of the line array in the operating frequency band(1.88-2.7GHz)is 15.7 d Bi,and VSWR <1.5.Based on the antenna array with 10 elements,a new antenna plane array is designed with 8-channel and ± 45 ° dual-polarized.By optimizing the element spacing of the antenna plane array,the antenna array(length L = 802 mm,width W = 331 mm,high H = 25mm)is reduced by 50% compared to the original size.The measured results satisfy the requirements of the base station antenna,and have a good application prospect.3.Antenna array with 10 elements is designed based on the bowtie dipole antenna.Through HFSS software to optimize the element spacing,reasonable control of the coupling among the elements,compared to the original antenna array length reduced by 43%.The simulation results show that the maximum gain range of the line array is 11.5 d Bi to 17.2 d Bi,and the VSWR is less than 1.5 in the operating frequency band(1.71GHz-2.7GHz).Its horizontal lobe width range of 66 degrees to 82 degrees,and vertical lobe width range of 8 to 16 degrees.4.A feed network is designed for the antenna array.In this thesis,three kinds of broadband power dividers are designed respectively.The three power dividers were improved on the basis of the Wilkinson power splitter.The bandwidth of the power divider can be extended by loading the fan-shaped bracnhes.The power splitter achieves good transmission performance over the entire operating frequency range(1.71GHz-2.69GHz).