Research On Orbital Angular Momentum Antenna Based On Artificial Electromagnetic Materials

In recent years,with the development of wireless communication technology,people's living standard has been greatly improved.However,with the increasing number of wireless terminal and the demand for wireless communication,still need new technology to improve the rate of communication and spectrum efficiency.In this situation,orbital angular momentum as a new technology has entered people's field of vision.In theory,this new technology can be realized a infinite amount of signal transmission in a frequency band.At the same time,the orbital angular momentum of the electromagnetic compatibility is great.This technology is expected to raise the maximum capacity of communication system,thus,it has wide development prospectsHowever,The generated methods of orbital angular momentum still has limitations,the current commonly used methods have antenna array and spiral phase plates and so on.Based on this background,this paper has carried on the further research and exploration about the generated method of orbital angular momentum.First of all,this paper simply explains the theory about orbital angular momentum.Then introduces the basic concept of orbital angular momentum,basic characteristics,research status at home and abroad related theory and its reuse.Basic introduces the basic concept and the research background of orbital angular momentum theory.And briefly introduces the commonly used classification of orbital angular momentum generated and detection methods.This paper also introduced the basic working principle of artificial electromagnetic material,provides the theory support for antenna design.Based on artificial electromagnetic material,this paper respectively designed electromagnetic vortex arrays of type reflection and transmission type.According to combination method.This paper designed an artificial electromagnetic unit about reflection type.the structure of the unit is composed of the Jerusalem cross structure and square ring type structure.Based on its equivalent circuit model,The final parameters can be determined.And the reflection phase adjusting range can reach 0 degree to 360 360 degree.Also,the reflection phase of phase curve is similar to a straight line.By controlling the size change to get the vortex arrays of reflection type,can be successfully get electromagnetic waves which carry orbital angular momentum.According to the principle of Pancharatnam-Berry Transmission,This paper designed an artificial electromagnetic unit about transmission type.Basic on this principle,When the incident wave is circular polarized,the phase can be compensated arbitrarily in 0 to 360 degree by rotating the unit.Based on this principle,this paper designs a artificial electromagnetic unit of transmission type by the method of changing the basic cross unit.This unit can effectively control the transmission phase and also has excellent transmission performance.Because of the requirement of circular polarization wave excitation,this paper successfully designed a circular polarized horn antenna as the feed source.According to the principle of unit rotation,the unit is set up to obtain a transmission electromagnetic vortex array.According to the simulation results of commercial software HFSS,the feasibility of the unit design is proved,and the theoretical support is provided for the subsequent research.