Research On Antenna Function Control Based On Novel Materials

With the rapid development of communication technology,higher requirements and challenges are put forward for the antennas as the front end of communication systems and wireless detection systems.The technology of using traditional metal and medium to design and fabricate antenna is becoming more and more mature.However,there is a huge research space to improve the antenna performance by using the unique material properties of novel materials.In recent years,function control technology has been widely concerned by domestic and foreign researchers and has been applied in many fields such as communication,radar and detection.Combined with the advantages of novel materials and antenna function control,a novel method of antenna function control based on novel materials is proposed in this thesis.In terms of novel solid material used as radiator supporting,novel liquid material used as radiating and plasma used as environment,the thesis studies the antenna function control methods based on bistable composite material,liquid metal material and plasma.In addition,the function control antennas based on solid bistable material,the function control antennas based on liquid metal material and the function control antennas based on plasma effect are studied respectively.The function control characteristics of the antennas are achieved based on the novel structural/electromagnetic properties of the materials mentioned above.The technical solution of designing the function control antennas based on novel materials is proposed on the basis of the exploration of the interaction between the intrinsic properties of the materials and the radiation structure of the antennas.The research content of this dissertation mainly includes the following four parts:Initially,the basic theory analysis method of realizing function control antennas based on novel materials are intensively studied.The meaning of function control antennas is given to clarify the functional concept of the novel materials antennas designed in this thesis,and the reconfiguration is equal to the function control.An equivalent array radiation model is proposed to analyze and verify the radiation characteristics of antennas by means of simulation and calculation.In addition,the interactions between materials and antennas are explored and researched.The basic properties of the new materials are introduced,and the relationships between the antenna structures and the material properties are established based on the bistable composite material’s double configurations,liquid metal’s fluidity and plasma’s electromagnetic parameters.Secondly,the method of the antenna function control based on bistable composite materials is proposed,and two function control antennas using bistable glass-fiber composite materials are designed.One is based on bistable composite cylindrical shells,and the other is based on bistable composite laminates.Furthermore,this bistable composite materials have two stable configurations and can maintain one of the two stable configurations without a continuous power input.Depended on the double configuration characteristics of such materials,the function control antennas with reconfigurabilities are designed by using bistable composite materials as the substrates to carry the metal radiators which have specific structures.The two antennas realize polarization and pattern reconfigurations.Compared with the traditional reconfigurable antennas,none of the redundant structures or control circuits is introduced in the two antennas.Thirdly,the method of the antenna function control based on liquid metal Galinstan is proposed,and the function control antenna using liquid metal is designed.The method of radiation direction reversal obtained by loading slots in the middle of the radiating elements of printed Yagi-Uda antenna is analyzed theoretically and verified by practical example.By adopting the loading slots principle and the mobility of liquid metal,a pattern and frequency reconfigurable printed Yagi-Uda antenna is designed.This antenna uses air pressures to control the positions of liquid metal poles and achieves five working states.Finally,the method of the antenna function control based on modulation effect of plasma is proposed.An end-fire broadband high gain low-side lobes dielectric-rod feed source antenna applied to plasma environment is designed and studied.The impedance bandwidth of this antenna is broadened by using tapered structures,double ridged waveguide structure and four wedged matching dielectric block.Furthermore,the shape of the dielectric rod is improved based on the traditional conical rod.By using the combination of the double circular truncated cone and one hemisphere structure,higher gain is obtained for this antenna.The other feed source antenna is a low-profile omnidirectional wideband dual-polarized antenna.This antenna is a combination of vertical polarization(VP)and horizontal polarization(HP)elements.VP element is a printed modified monopole and HP element is a printed 8-element circular connected Vivaldi antenna array.By means of simulation,the above two antennas loaded with the plasma medium model are analyzed,which verify the feasibility of the radiation enhancement effect.The two antennas have broadband characteristics,which can cover a variety of communication frequency bands,and the gains of the antennas can be controlled by loading plasma.The dissertation focuses on the study of antenna function control based on novel materials.Based on the study and analysis of the relationships between material properties and antenna radiators’ structures,the realization mechanism of function control is explored and the design methods of function control antennas are established.The bistable composite material reconfigurable antennas,liquid metal reconfigurable antenna and gain control antennas based on plasma modulation effect are designed.The dissertation provides design ideas and technical methods for function control antennas based on novel materials,and it will provide strong technical support for the future research of function control antennas based on novel materials.