Development of a wide-band low-noise traveling-wave amplifier at X-band

One of the most difficult aspects in the development of a low-noise traveling-wave amplifier is that of producing low-noise performance over a wide range of frequencies. Although the traveling-wave tube is inherently broadband with respect to its gain and to many of its other characteristics, its noise figure typically is a sensitive function of frequency. Particular effort was made to investigate the bandwidth limitations of the low-noise performance. As the experimental results presented in the following paragraph show, wide-band low-noise behavior was achieved. It was found that such behavior can be obtained by observing certain design principles, such as designing for high space-charge factor and for high plasma-reduction factor.