Investigations of non-linear spectral behavior in multi-toned helixtraveling wave tubes

摘要

Summary form only given. This research experimentally examines theharmonics and intermodulation products inherent when amplifying multiplefrequency signals in traveling wave tubes (TWTs). Laboratorymeasurements of these phenomena in several TWTs are compared topredictions from computer simulation codes. To date, this research hasprimarily focused on the empirical characterization of commerciallyrelevant broadband TWTs. Standard commercial tubes are used, as well asa custom-modified research device, jointly designed by UW andNorthrop-Grumman investigators. This modified TWT includes multipleoutput taps along the helix, providing a unique means to observe theevolution of the RF spectrum at various axial positions, as well as thecold versus beam-loaded dispersion characteristics. The steady-state andtransient output spectra are recorded from the linear gain region wellinto saturation, and the spectral purity of the outputs are compared.The device gain versus frequency and input power level are presented forsingle-toned and multi-toned signals