Study On The Effect Of Carrier Platform And Plasama Sheath On Antenna Performance

Antenna radiation characteristics such as communication with the outside world and remote sensing are often affected by the surrounding environment.The main influencing factors include antenna carrier platform,antenna cabin,radome,and plasma sheath formed under hypersonic flight conditions.These factors may cause changes in the distribution of the antenna radiation field in space,distortion of the pattern,impedance mismatch,change in the standing wave ratio of the return loss,etc.,which may further cause the antenna system to malfunction or even more serious accidents Occurs,so it is of theoretical and practical value to study the influence of the carrier platform and the plasma sheath on the antenna.Based on the existing theory,this paper builds a carrier platform to the antenna influence measurement system in the microwave darkroom.The system is used to study the influence of the antenna cabin on the antenna performance,and the relevant parameters are measured and calculated.The radiation characteristics of the antenna under the sheath of the plasma sheath were studied by ray tracing method.The reasons for the variation of the radiation characteristics of the antenna under different parameters were analyzed.The main work of this paper as follows:1.The experimental and ray tracing methods needed for the influence of the carrier platform and the plasma sheath on the antenna are introduced.Firstly,the basic methods and steps of antenna performance measurement are introduced,including antenna pattern,gain and polarization characteristic test methods.Secondly,Field calculations are carried out to study the variation of reflection coefficient and transmission coefficient with incident angle.the ray tracing method in inhomogenous plasma sheath is given.The path calculation and field in ray tracing method are mainly analyzed,which lays a theoretical foundation for the subsequent research.2.Experimental study on the influence of antenna cabin on antenna performance.The antenna measurement system is built in the microwave darkroom environment.The experimental system consists of a signal generator,a vector network analyzer,a transmitting antenna,an antenna cabin system,a receiving antenna and a data processing system.The system is used to measure the pattern,phase,gain and cross-polarization characteristics of the antenna under the influence of frequency,position and other parameters in the antenna cabin,and the antenna performance change under the influence of the antenna cabin is obtained.3.The ray tracing method calculates the radiation pattern of the antenna under the influence of the 3D plasma sheath.The plasma sheath flow field is divided,and the discrete plasma sheath flow field data is subjected to body splitting.For some cases without electromagnetic nodes in the splitting unit,the corresponding electromagnetic parameters are calculated by an improved search algorithm.Calculate the propagation path of electromagnetic wave in each direction of the plasma sheath split model,calculate the propagation loss based on the split model and the transmission attenuation and phase of TE wave and TM wave by using the general solution plane wave of electromagnetic wave in the plasma.Change to obtain the electric field pattern that eventually passes through the sheath.The changes and changes of antenna performance under different aircraft heights,different Mach numbers,and different angles of attack are analyzed.Finally,the effects of the antenna case and the plasma sheath at the same time on the antenna were calculated,and the reasons were analyzed.4.Calculate the influence of dust plasma on antenna performance and make a visual software interface.The radiation pattern of the horn antenna under different dust parameters(dust particle density,dust particle radius,relaxation rate)was studied.The ray tracing method is used to calculate the influence of the plasma sheath on the characteristics of the antenna antenna.The calculation part is packaged into a dynamic link library,and the program is visualized by using the winform platform,that is,only the input antenna parameters and the sheath flow field data are needed to obtain the antenna in the plasma sheath immediately.The radiation characteristics under the influence of the set.