Application Research Of Graphene In Antenna Design

With the advancement of China's wireless communication technology innovation and development strategy,higher requirements and challenges are put forward for the performance of wireless communication equipment.In recent years,the preparation technology of graphene has gradually matured.Due to its excellent physical properties such as light,electricity and heat,it has become a hot spot in research and application in various fields.Based on the unique advantages of graphene materials in improving antenna performance,in-depth theoretical and experimental research will help to bring into the enormous scientific and economic value of graphene materials in the field of wireless communications.And the technologies of advanced wireless communication will promote rapidly.This thesis focuses on the research and application of graphene in antenna design,including the following four aspects: 1.The research progress and current status of graphene are introduced,and the basic theory of antenna design is expounded,including:(1)basic parameters of antenna,radiation mechanism of microstrip antenna.An ultra-wideband quaternary MIMO antenna was designed and tested.(2)Graphene conductivity model,dielectric constant model,and calculation and simulation methods of graphene;the dipole antenna which graphene as a radiation patch is simulated to analyze the variation of the antenna performance with the chemical formula which loaded on the graphene.And the performance is compared with the metal dipole antenna of the same size.The advantages and disadvantages of each antenna are analyzed.2.A dual-frequency terahertz antenna was researched and designed.According to the characteristics of current flow and electromagnetic radiation when the graphene sheets placed around the metal radiation patch,several antennas were designed.Including: rectangular graphene sheets antenna,"T-shaped" graphene patch antenna,"?-shaped" graphene patch antenna.Through detailed comparison of various structures,it is finally determined that the antenna loaded with the "?-shaped" graphene patch antenna has a stable operating band and good performance,and is expected to be applied in practical engineering.3.The graphene-based frequency reconfigurable microstrip antenna is studied.The graphene stub structure is placed in the metal rectangular ring.And the equivalent transmission line model is established for the stub to calculate the total input impedance of the antenna.In combination with theoretical computational analysis,the relevant parameters of the stub are optimized to improve the performance of the proposed reconfigurable antenna.After simulation and test analysis: the DC voltage loaded on the graphene sheet can be changed to realize the reconfigurable antenna frequency.On this basis,three-section frequency reconfigurable antennas are designed.By adjusting the voltage applied on different branches,the reconfigurable antenna operating frequency can be realized,which provides a new idea for the application of graphene in the microwave band antenna.4.A cylindrical radome was studied.A graphene-based frequency-selective surface unit was designed,and a cylindrical radome was designed based on the unit structure.The FSS unit was evenly distributed on the side of the cylinder and on the upper and lower sides.In order to verify the beam reconfigurable of the radome,an omnidirectional dipole antenna operating in the FSS passband frequency band was designed.And the dipole antenna was placed in the radome for simulation test.The result showed that the beam reconfigurable of the dipole can be achieved.Also,the antenna gain is also improved.The radome of this design is likely to be used in terahertz beam scanning in the future.