UNSYMMETRICAL-DIELECTRIC LOADED HELICAL STRUCTURE WITH NEGATIVE DISPERSION CHARACTERISTICS AND WIDEBAND TRAVELING-WAVE TUBE USING THE SAME

摘要

PURPOSE: An unsymmetrical-dielectric loaded helical structure with negative dispersion characteristics and a wideband traveling-wave tube using the same are provided to achieve negative dispersion characteristics with larger phase velocities of the high-frequency waves than those of the low-frequency waves. CONSTITUTION: An unsymmetrical-dielectric loaded helical structure comprises a helix(10) disposed between an electron-beam-generating apparatus and an electron beam collector; at least one first dielectric supporting rod with a first dielectric constant, for supporting the helix; a plurality of second dielectric supporting rods with a second dielectric constant, for supporting the helix; and a metal envelope(50) for enclosing the helix and the first and second dielectric supporting rods, wherein the first dielectric constant is greater than the second dielectric constant.