Research On Orbital Angular Momentum Antenna Based On Artificial Electromagnetic Materials

All radio communication,broadcasting,radar and other engineering systems use radio waves to work.The transmission and reception of radio waves are done by antennas.Nowadays,we need to design antennas with high gain and wide frequency bands,and have large scanning angles to cope with today's technological situation.Therefore,the research of ultra-wideband antennas has more special significance and value.In this paper,an ultra-wideband array antenna is designed by using the coupling effect between antennas.Firstly,the index of the antenna is briefly introduced.Then the theory of the tightly coupled antenna is analyzed and explained,and the equivalent circuit model is introduced.Then the antenna is designed based on the equivalent circuit model.For the design of the antenna,different functions are first selected as the boundary of the antenna unit,and then the influence of different coupling strength on the antenna bandwidth is analyzed.Next,consider the effect of coupling strength on the antenna gain,and summarize the relationship between coupling strength and bandwidth as well as gain.Due to the large bandwidth of the antenna,this will cause an inversion stack at a specific frequency under the action of the reflector,which will cause a short circuit effect,so a frequency selective surface is designed to suppress the influence of the reflector.The feed network of the tightly coupled antenna is designed,and finally a feed transition structure from 50 ohms to 200 ohms is designed and satisfied.Low profile.Finally,the designed antenna and frequency selection surface were processed and assembled,and put into the platform test.The simulation and design finally matched,and a tightly coupled array antenna with low profile based on frequency selective surface was designed.