Research On Sub-6 GHz Base Station Antennas And Array Scanning

The rapid development of the fifth-generation communication system(5G)conforms to people's pursuit of fast and efficient transmission of information since ancient times.Of course,the arrival of the 5G era has brought challenges to mobile communication technology,and base station antennas,as the “eyes and ears” of mobile communication systems,also need to be upgraded accordingly.5G base station antennas use large-scale array antennas to implement Massive MIMO technology and beamforming technology,thereby greatly increasing the communication rate.However,the large-scale arrays used in 5G base stations greatly increase the number of antenna elements,and at the same time increase the volume,weight,and cost of the antenna array.On the other hand,5G large-scale arrays occupy a lot of space for antennas in other frequency bands,making the distance between antennas getting closer and closer in a limited space,causing the coupling problem to become more and more serious.Therefore,how to effectively reduce the volume and weight of the 5G array and reduce the cost of the antenna array is a question worth considering.The design of an antenna array with excellent performance must start with the design of the antenna unit.The antenna unit is small in size,low in cost,and has good performance.Therefore,in the design process of the antenna unit applied to the Sub-6GHz frequency band in 5G,it is necessary to ensure the basic broadband characteristics and fully cover the working frequency range.On the basis of achieving good antenna performance,the advantages of compact structure design,miniaturization,and low cost can be achieved,so that the volume,weight and cost of the 5G array can be effectively reduced.On the other hand,array scanning is a very promising technical solution in 5G wireless communication technology because it has a wide frequency band and steerable beams.Coupling problems will inevitably occur in the design process of array antennas,suppress the coupling between antennas,and then improve the low isolation caused by coupling,so that the antenna array can achieve high isolation and wide-angle scanning performance.This is an important research content.The research work of this dissertation is as follows:1.The principle of miniaturized patch base station antenna is studied.On the basis of the patch antenna designed here,two broadband antennas were redesigned.One is a broadband antenna based on parasitic patch loading,and its relative working bandwidth can reach 36%(0.67-0.98 GHz),which can completely cover the frequency range of LTE700 / GSM850 /GSM900.The other is to reform the feed structure,complete the design of the single-ended feed structure,and ensure the broadband characteristics.2.Designed a single-ended differential signal-fed patch antenna.The designed antenna has outstanding filtering characteristics.The antenna is based on a miniaturized patch antenna,which uses the current distribution characteristics of an open-ended half-wavelength microstrip line to complete single-ended differential signal feeding,and then achieves antenna filtering through a series E-type resonator characteristic.3.A slot patch antenna is proposed,the impedance bandwidth of the antenna can completely cover the designed working frequency band.Not only that,the designed antenna has better polarization isolation characteristics than traditional cross dipole antennas and patch antennas.After the application of cavity-backed isolation plates,the polarization isolation and inter-unit isolation in the binary array are achieved at the same time.Improvement.4.Introduced the related theory of array scanning.Based on the theory,two scanning arrays were designed.First,four patch antennas were formed into a linear array by designing a one-to-four power divider,and then four linear arrays were staggered to form an area array.The isolation baffle improves the coupling problem between the sub-arrays,which not only achieves good inter-column isolation characteristics,but also completes the scanning characteristics.Then the slot patch antenna is the array element,and the designed one-to-six power divider is used to design the linear array and the area array.In addition,through the back cavity structure,the isolation between columns and the polarization isolation are improved.The designed scanning array achieves good isolation performance and wide-angle scanning characteristics.