Traveling wave tube with frequency variable sever length
AssigneeVarian Associates, Inc.
InventorMichael L. Neubauer
Life of this patent
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Abstract
In a traveling wave tube (TWT) with a non-dispersive interaction circuit such as a helix, the length of the circuit in wavelengths, and hence the gain of the tube, varies with the frequency. The variations of gain over a very wide bandwidth can cause oscillation problems. The invention provides an inverse variation with frequency of the physical length over which the circuit interacts with the beam. This is done by resonant attenuators coupling to the interaction circuit over various lengths depending on their resonant frequency, the attenuation being enough to effectively remove the interaction circuit wave. The attenuators are preferably formed of resonant sections of slow-wave circuit deposited on longitudinal ceramic rods such as the helix support rods.
Claims25
A traveling tube having internal gain compensation, comprising:
- A helix-type interaction circuit for supporting interaction of an electron beam with microwave signals over an operable band of frequencies, said interaction tending to produce a gain varying with frequency, a first attenuator resonant at a first frequency within said operable band and coupled to said interaction circuit over a first length of said interaction circuit, and a second attenuator resonant at a second frequency within said band and coupled to said interaction circuit over a second length, said first and second frequencies being generally identified with frequencies in said operable band whose gain is sought to be compensated, whereby gain of said frequencies within said operable bandwidth is automatically compensated internally.
An internally gain-compensated traveling tube comprising:
- a helix-type interaction circuit for slow-wave interaction of microwave signals with a linear electron beam over a wide operating band of frequencies, said interaction tending to produce a gain which varies with frequency;
- a plurality of resonant means within said tube, each resonant at a different respective frequency, each extending over a respective different length, each adjacent said interaction circuit, for electromagnetically coupling into said interaction circuit a respective frequency-selective loss to internally compensate said frequency-varying gain automatically over said operating band.
A traveling wave tube having noise-resistant internal gain compensation comprising:
- a helix-type slow-wave circuit having an input end for microwave signals, said signals interacting with a linear electron beam over a selected band of frequencies, said interaction tending to produce a gain which varies with frequency,
- a dielectric rod near said circuit extending in the direction of the axis of said slow-wave circuit;
- and
- a first resistive conductor shaped to form a circuit resoanant at a first frequency within said tube, said conductor being attached to the surface of said rod so as to extend over a first length of said slow-wave circuit;
- and
- a second resistive conductor shaped to form a circuit resident at a second frequency within said band, said conductor being attached to the surface of said rod so as to extend over a second length of said slow-wave circuit;
- said conductors both being spaced away from said input end, said conductors providing respective different degrees of attenuation about said first and second frequencies to compensate said gain varying with frequency without degrading the anti-noise properties of said tube.
Dependencies are inferred from the claim text.