Study On Energy Transmission System Of Terahertz Vacuum Devices

With the wide application of vacuum devices in communication,radar and other fields,the research on vacuum devices that can be applied to the terahertz frequency band has become one of the current research hotspots.As the core part of the vacuum device,the energy transmission window plays an important role in ensuring the vacuum degree and transmission performance of the device.However,due to the size co-existence effect,the processing and assembly of device in the terahertz frequency band have greater difficulties,and as the frequency continues to increase,the conductor loss in the waveguide will further increase.This paper takes the energy transmission system of terahertz vacuum device as the research object.The energy transmission window of the vacuum device is combined with the Gaussian horn of the quasi-optical transmission system to obtain easy processing,reduce the loss of the waveguide wal,and use the characteristics of the Gaussian beam to achieve free space comparison.Terahertz vacuum device energy transmission system for long-distance transmission.The main research contents of this paper are as follows:(1)Design and realization of 340 GHz energy transmission window.First,according to the equivalent circuit theory of the improved box window,the basic size of the model is quickly obtained,and the model obtained by the numerical solution is optimized using the CST software.Finally,three improved box types with different dielectric window materials are designed.The windows are all satisfying to have a bandwidth of 30 GHz near the 340 GHz frequency,and the return loss S11<-20 d B,and the transmission coefficient S21>-1d B.Secondly,according to the model parameters obtained by the simulation,the 340 GHz sapphire modified box window was processed and tested,and the sapphire window was metalized by magnetron sputtering,and the welding of the energy transmission window was completed according to the new processing and sealing scheme.In the air tightness experiment test,the cold test result is in the 330GHz～350GHz frequency band,S11<-16.7d B,S21>-2.75 d B.Finally,the over-mode energy output window is analyzed according to the impedance matching method,and the theoretical model of the 340 GHz over-mode energy output window is calculated.After optimization by the CST software,the final simulation result is in the 322GHz～337GHz frequency band,S11<-20 d B,S21>-0.5d B.(2)Design of 340 GHz quasi-optical transmission system.According to the relevant theories of the quasi-optical transmission system,the model of each part of the 340 GHz quasi-optical transmission system that meets the design requirements is first constructed,and the mode converter that can convert TE10 mode to TE11 mode is obtained,and the TE11 mode can be converted to Gaussian beam and A Gaussian horn with a transmission efficiency of 98.5%.Secondly,the overall transmission performance of the 340 GHz quasi-optical transmission system is optimized.The final simulation result is that the transmission efficiency of the 340 GHz Gaussian beam is 92.1%.Finally,the overall optimization design of the energy transmission system for the 340 GHz terahertz vacuum device was carried out,and the conversion of the TE10 mode to the Gaussian beam was successfully realized.