Design Of Electromagnetic Vortex Microstrip Array Antenna

The demand for higher communication rates and the increasing shortage of spectrum resources calls for new technologies to increase the capacity of wireless communication channels.In recent years,the Orbital Angular Momentum(OAM)antenna,which can transmit multiple signals simultaneously with frequency multiplexing,has attracted extensive attention from domestic and foreign experts.In this paper,the basic principle of OAM is firstly expounded,the process of OAM multiplexing,four methods of generating OAM vortex electromagnetic wave in microwave frequency band and four ways of feeding from OAM array antenna are introduced.Then,based on the microstrip antenna technology,the antenna radiation mechanism and the design process of the array antenna are expounded,the calculation process of the size parameters of four different radiation patches is analyzed,and several methods commonly used in the microstrip antenna broadband technology and circular polarization technology are summarized.After combined with 3D electromagnetic field simulation software design for four different patch shape OAM microstrip array antenna,the simulation of the proceeds of the return loss,electric field amplitude diagram,direction diagram etc.The results show that the design of the antenna array can effectively produce the OAM characteristics of vortex electromagnetic wave,and different OAM modal of vortex wave can transmit data without interference at the same frequency and the same time.A rectangular OAM microstrip array antenna is designed,which can generate 7 kinds of vortex electromagnetic waves in different OAM modes simultaneously at two different frequency points.In this paper,a circular slotted microstrip array antenna is designed by using the "meander" technology.The antenna can work at double frequency points,and the eddy electromagnetic wave radiated at different frequency points is found to rotate in opposite direction.The antenna is made into a real object and tested,and the measured results are in good agreement with the simulation results.The circular polarization technique is used to simulate the design of an array antenna which can radiate circular polarization characteristic vortex electromagnetic wave.Finally,based on the principle of Butler matrix,each unit module of the feed system is designed and relevant size parameters are optimized by electromagnetic simulation software.The results show that the designed single-layer microstrip 4×4 Butler matrix feed network has good matching characteristics and can effectively realize phase shift.