Research On Phased Array System And Key Technology For Stereo Coverged Large-scale Array

With the continuous maturity and development of the fifth-generation(5th-Generation,5G)mobile communication technology,the large-scale deployment and commercial use of 5G are in full swing all over the world.An important application scenario of 5G is the ultra-large-scale connection scenario for the "massive Internet of Things".The powerful connection capabilities of 5G can quickly promote the deep integration of various vertical industries,such as building smart cities,realizing the internet of vehicles,and building a drone networking platform,etc.This full-scene communication background puts forward new requirements for the coverage capability of the communication system,requiring the system to have a wider and more flexible full-space beam coverage capability.The terrestrial base station not only needs to achieve downward coverage of the ground equipment,but also needs to have the ability to radiate and communicate with the headspace.A key technology in5 G communications is beamforming technology based on large-scale antenna arrays.Beamforming technology can expand the dimensionality of communication system utilization,thereby improving spectrum efficiency and expanding system capacity.It is against this background that this article has carried out research on the large-scale array antenna beamforming system and its key technologies in a three-dimensional coverage scene.The antenna array of the existing communication equipment is mainly to realize the coverage of the ground terminal and realize the scanning of the azimuth.According to the application scenarios of the three-dimensional overlay array,this paper realizes the development of the headspace-oriented overlay array in the three-dimensional overlay array,and studies some key technical difficulties of the three-dimensional overlay array.The paper adopts the tile structure with the active circuit and the patch antenna arranged vertically,which reduces the profile of the active integrated antenna array,which can effectively solve the problem of the three-dimensional array.In the design of the antenna unit of the array,the paper adopts a modular and detachable structure,and develops a dualpolarization filter antenna,which reduces the complexity of the design and improves the system capacity and out-of-band suppression.In the design of the miniaturized RF front-end,the stripline power divider network is used to save the PCB layout area and solve the problem of the thinner branch line of the power divider in the stripline.The hairpin filter is designed by the method of semitheoretical model and semi-numerical analysis.The fast optimization method of the broadband power amplifier improves the overall performance of the radio frequency front end.The phased array developed in this paper has 32 dual-polarized antenna units and 64 radio frequency channels.The system works at 3.5 GHz,the channel bandwidth is 200 MHz,the total area of the array circuit is 337mm*373mm.The beamforming system developed in this article has been tested for air interface and radio frequency conduction.The array is tested for beam scanning in two dimensions within a range of ? 45°,the main lobe 3d B beam width is about 14°,the antenna array gain is 19.5d B,the beam gain fluctuation of different pointing is around 3d B,and the gain fluctuation of different frequency points at 0° pointing is less than 2d B;using 100 MHz bandwidth QAM-64 signal as the test signal,air interface demodulation tests are performed on the array in three receiving states of vertical polarization,horizontal polarization and 45° polarization,the EVM is around 1%;two 50 MHz QAM-16 data streams are used to test the performance of multi-user communication on the array,the demodulation EVM of the two data streams are 3.69% and 4.14% respectively.In the frequency band of 3.4GHz?3.6GHz,the average gain flatness of each channel in the receive mode is1.8d B,the noise figure is about 1.6d B,the average gain flatness in the transmit mode is 0.9d B,and the OP1 d B of the link in the large signal test of the transmit mode is 28.8d Bm,the spurious suppression is greater than 50 d Bc.The test results show that the uniformity and RF performance of the array are good.