| Traveling wave tube (TWT) consists of electron gun, slow-wave structure, collecting region, cut-off attenuator, and output termination ,etc. However, the reflection caused by the joint of each part affects the performance of TWT. Especially in amplitude and phase coherent TWT, the reflection caused by the inconsistency of each part has serious influence on the frequency response between gain and phase. This further affects the quality and yield rate of the TWT. Therefore, it is necessary to research the inconsistency of TWT.This dissertation aims to study the technique of autotest in the mismatch caused by the attenuator and the output termination in the coupling cavity slow-wave structure. Because the basic theory is the multi-point method, studying this theory is necessary.Then,on the basis of multi-point method it can reach the aim.This dissertation is to set up a series of measurement equipment which is consist of testing platform, servo system, phasic network analyzer (PNA) and computer. The whole measurement process is controlled by the software program. The precise location of reflection probe is completed by operation of servo motor controlled by software. Then by applying Visual Basic 6.0 with application program in PNA, we complete the program of the measurement software. After that, we complete the mismatch measurement of the coupling cavity slow-wave structure, and also improve the testing software. |
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