Design Of Wideband Dual Polarized Wide-angle Antenna

In the development of mobile communication technology,Wireless Local Area Networks also develops synchronously.As a short-distance wireless communication technology,Wireless Local Area Network(WLAN)technology and mobile communication technology complement each other and play a huge role in some occasions.The base station antenna is indispensable for both mobile communication technology and Wireless Local Area Network technology.With the increasing complexity of the communication system,the performance of the base station antenna has been put forward more and more stringent requirements.Polarization diversity is an important technology to resist multipath fading,which can effectively save antenna cost and space cost.In some scenarios,the direction of main lobe is required to be changed flexibly.Sometimes the main lobe is required to have a large coverage,so that the scanning angle of the antenna is required to be higher.The phased array antenna is a array antenna which can adjust the deflection of the main beam by electronic control device.Instead of mechanical rotating parts,it can flexibly change the shape and direction of the beam to form multiple beams.It has become an important development direction of antenna technology to search and track multiple targets quickly.In order to improve the service quality of WLAN in some public places with large traffic,this paper studies the WIFI base station antenna and broadband scanning characteristics in 5 GHz unauthorized band.Firstly,this paper introduces the research status of broadband dual-polarized base station antenna and broadband beam antenna at home and abroad,and briefly describes the basic theory of array antenna,which provides a basis for the design of antenna elements and arrays in the future.Then the basic theory and common technology of microstrip antenna are studied,and a single polarization broadband and wide angle base station antenna unit is designed.The unit works at 5.15GHz~5.875 GHz,the maximum gain is 5d B,and the half power beamwidth on E plane is ±60 degrees.The feasibility of microstrip antenna as a broadband base station antenna unit is verified.On this basis,a dual-polarized wide-beam base station antenna unit is proposed.The results show that the antenna achieves 45 oblique polarization in the range of 5.15 GHz to 5.875 GHz,and has a low cross polarization level.The half power beamwidth in the scanning direction can still reach 60 degrees and the maximum gain is over 3d B.Then,the unit is composed of 5 X 8 arrays,8 Chebyshev low sidelobe arrays in the direction of non-scanning plane,and 5 tight coupling arrays in the direction of scanning plane to widen the beam width of scanning plane.The other elements are connected with matching loads to study the active pattern characteristics of the antenna.The results show that the 3d B beam width of the active pattern in the 5.15GHz~5.875 GHz band is over ±60 degrees,the cross-polarization level is below-10 d B,and the maximum gain is more than 12.8 d B.Finally,the phase-controlled scanning characteristics based on the active pattern are obtained by using the principle of pattern multiplication.The results show that the scanning angle of the array reaches ±60 degrees in the range of 5.15 GHz to 5.875 GHz,and the gain fluctuation in the range of scanning is no more than 3.7 d B,most of the cross polarization level is below-15 d B.,the sidelobe level is about-12 d B,and the scanning performance is good.