Microwave Signal Transmission Technology Of The Helix Traveling Wave Tube

Traveling wave tube(TWT) is one of the most important electricity vacuum devices which is a kind of high power, high gain and broad-band microwave millimeter wave amplifier. They are widely used in communication, radar system, and electronic warfare. As one of the important application of helix TWT, Space TWT is the pivotal part of repeater and synthetic aperture radar's transmitter in satellite and it is taking an irreplaceable role in high power and high frequency region. With the development of the spaceflight project in our country, the space TWTs from C band to Ka band are in imminently needed.With the guide of the research group in "research and development K band space TWT", the high frequency system of the helix TWT is researched based on the predecessor's results in this paper. Several important and valuable results are listed as blow:1. The couplers of the helix TWT are researched. Based on the theory of transmission line, the input and output couplers of a K band space TWT are designed using CST MWS. The simulation VSWR of the couplers are smaller than 1.5 in the whole frequency region. The couplers are tested at the same time. Compared the results in theory with that in the cold test, it indicates that using CST MWS to design the couplers can not only satisfy the request of the actual project, but also reduce the cost and the designing time.2. In order to improve matching performance, the attenuator of helix TWT is tested using the microwave-testing method. The relative attenuation curve is got by measuring. Compare the relative attenuation curve with the attenuator's VSWR, the relationship of the relative attenuation curve and the VSWR is established. So, in the actual testing, measuring the relative attenuation curve can test the matching performance fast and effectively and also provide powerful gist for improving the attenuation making technology.3. The helix slow wave structure(SWS) is researched. Dispersion and interaction impedance are measured via non resonant method. Compared the results in theory with that in measure, the error is less than 5% in measuring the dispersion, and in measuring interaction impedance, the error is less than 20%. It is shown that the measuring the dispersion and interaction impedance via non-resonant method is an effective method in researching the helix slow wave structure.