Design And Reserch Of Smart Antennas For TD-LTE

The base station antennas are widely used in RF/microwave communication,they play an important role in the performance of the whole network communication system.With the improvement of 4G network traffic and the data rate,the mobile communication system is becoming more intelligent and more efficient.The smart antenna for LTE system is researched and developed in this paper,focusing on the design of oscillator components,calibration circuits,power dividers and antenna.In this paper,the operating principle of smart antennas,MIMO,the shaped-beam technology is analyzed.Through the comparison of metal die-casting oscillator and PCB oscillator both in structure and radiation characteristics,PCB oscillator is chosen to be the radiation unit to accomplish the miniaturization of antenna machines and have a better beam informs.The FAD band dual polarized PCB printing of TDD mode is designed later,with the full radiation pattern,wide and stable half power beam,and verify the loading subsidence column can play the role of debugging VSER by using the simulation software HFSS.The feed network is designed,which using stepped impedance matching transformation,and the power divider bandwidth is optimized.So the feed network operating bandwidth of 1710?1690MHz,VSWR<1.3.Based on the PCB oscillator designed,0.85 times of the wavelength corresponding to the main frequency is determined to be the best element spacing;then a linear antenna array of 10 elements is established using CST simulation software.the result well agreed with the actual result.Combined with the genetic optimization algorithms,the calculated weight of beam forming can be 6 degree below in the simulation of pattern synthesis in PCAAD.And the side lobe suppression reaches-25dB,meeting the requirements of TD-LTE base station's pattern synthesis.Expanding the 1*10 antenna array to a 4*10 FAD antenna array,but some frequency of the side lobe suppression and the cross-polarization don't meet the reasonable indexes even the 6 degree below is accomplished.