Title :
A theory of the attenuator-coated helical slow-wave structure of a traveling-wave tube
Author :
Jain, P.K. ; Basu, B.N.
Author_Institution :
Dept. of Electron Eng., Banaras Hindu Univ., Varanasi, India
fDate :
10/1/1988 12:00:00 AM
Abstract :
A theory of the attenuator-coated helical slow-wave structure of a traveling-wave tube has been developed by considering the helix turns to be effectively shorted by a resistive coating. Power propagating down the structure is interpreted for the interaction impedance in the presence of the attenuator-coating losses. The dependence of the attenuation and phase propagation constants as well as the interaction impedance on the surface resistivity of the coating, the operating frequency, the thickness/proximity of the envelope, the permittivity of the dielectric, and the pitch of the helix have been studied for two situations in which the attenuator coating is applied: (1) inside a dielectric tube that the helix fits into, the whole enclosed in a metal envelope: and (2) over a dielectric tube enclosure for the helix
Keywords :
losses; travelling-wave-tubes; TWT; attenuator-coated helical slow-wave structure; attenuator-coating losses; dielectric tube enclosure; envelope thickness; helix pitch; interaction impedance; metal envelope; microwave tube; operating frequency; permittivity; phase propagation constants; resistive coating; shorted helix turns; surface resistivity; traveling-wave tube; Attenuation; Attenuators; Coatings; Conductivity; Dielectrics; Frequency; Permittivity; Propagation constant; Propagation losses; Surface impedance;
Journal_Title :
Electron Devices, IEEE Transactions on
