| In recent years,with the development of micro-machining technology,some new structural processing technology has gradually matured,so that miniaturized power amplifier devices have been rapidly developed,such as planar traveling wave tubes,the main direction focuses on achieving high power,high frequency band,while taking into account the characteristics of miniaturization and low voltage.Focusing on the design goals of miniaturization and low voltage of traveling wave tubes,this thesis conducts in-depth research on miniaturized traveling wave tubes from the aspects of model simulation and processing and experiments,and the specific work content is summarized as follows:1.A suspended U-shaped microstrip line slow-wave structure applied to the W-band band is proposed.This U-shaped microstrip line slow-wave structure(SWS)is designed to increase the output power,and the basic principle is to increase the coupling impedance of the slow-wave structure by mounting the dielectric substrate to reduce the proportion of medium in the entire channel.Through detailed theory and simulation analysis,the optimization results are as follows: when the electronic beam voltage is11.8k V and the current is 0.2A,the output power can reach 96.6W at the operating frequency of 97 GHz,the corresponding gain is 21.09 d B,and the electronic efficiency is4.0%.The 3d B bandwidth is 92 GHz to 98 GHz.2.A suspended ridged microstrip line slow wave structure is proposed,and a metal ridge is added to the linear section of the microstrip line of the W-band U-shaped microstrip line slow wave structure,and there will be a strong longitudinal electric field above the periodic metal microstrip line,so that the added section of metal ridge can further increase the coupling impedance,and finally further improve the interaction efficiency of the microstrip line planar traveling wave tube amplifier.Compared with the coaxial input-output structure of the suspension model,the input and output mode of the rectangular waveguide is designed here,which simplifies the processing difficulty of the signal coupling structure.The simulation results show that when the electron beam voltage is 11 k V and the current is 0.1A,the output power at 97 GHz is 21.2W,the corresponding gain is 11.8d B,and the electronic efficiency is 1.93%.The 3d B bandwidth is 94 GHz to 98 GHz.3.A sheet beam electron optical system that meets the interaction requirements of W-band suspended ridged slow-wave structures is designed.First,by improving the structure of the Pierce electron gun,the required sheet electron beam electron gun was designed,and then the periodic cutting(PCM)focusing system that could be clustered with ribbon electron beam was designed.The joint simulation of the electron gun and the magnetic system was completed,and the effective distance of the electron beam that can be stably transmitted in the flow tube is 20 mm.This ensures the subsequent interaction of beam waves in the suspended ridged slow wave system.4.The experimental exploration of processing and assembly of the designed suspended slow-wave structure was carried out.The linear and curved mounted slow-wave structures were processed respectively,and their transmission performance was tested by "cold" experiments,and the results of the tests were analyzed and compared,and the test results showed that the experiment and simulation had certain errors,and the reasons for the errors were analyzed,and further optimization and improvement were made. |
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