| Hughes structure coupled cavity traveling－wave tube (CCTWT) is widely usedin modern communication and radar systems. Due to its features of wide bandwidth,high power capacity and simplicity of structure, CCTWT is hardcore in microwavevacuum system research. Band edge oscillations is inherent character to CCTWT,especially wide bandwidth and high gain CCTWT, so restraining oscillations is acomplicated problem to CCTWT research. This thesis effectively solves band edge andreflecting oscillations of a X band CCTWT.Band edge oscillations can be solved by arranging loss buttons in cavities. Thismeasure only act on upper cutoff bandwidth and no power wastage in work bandwidth,In addition, this technique does not affect on efficiency and gain characteristic. Whentube exports very high power and gain, it works steadily all the same.This measure of restraining reflection oscillations have perfect widebandmatching characteristic to slow wave structure and power transport installation. Perfectwideband matching characteristic contributed to not only restrain reflect oscillationsbut also reduction of gain fluctuation, which has very important practical meaning.CAD technology is widely used in designing and manufacturing TWT with thedevelopment of computer technology. High frequency and dispersive characteristics ofHughes slow wave structure employing loss buttons have been analyzed using CSTMicrowave Studio, on the other hand effect of loss button dimension to restrain bandedge oscillations is discussed. The article introduces design method of matchingcharacteristic about slow wave structure and power transport installation and analyseseffect factor.Finally, a Hughes slow wave structure employing loss buttons has been designedand manufactured, the experimental results are given. It is shown that self-oscillationhave been eliminated at arbitrary operation voltage. |
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