US3846664A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coupled cavity travelling wave tubes
Assignee: Teledyne UK Ltd
•
Filing: 1973-02-22
•
Granted: 1974-11-05
•
Expires: 1993-02-22
Abstract
Abstract A travelling wave tube having a coupled cavity slow wave structure is provided with velocity tapering to slow the speed of travel of an applied radio frequency wave at the output end of the tube so that it is maintained substantially in step with the decreasing velocity of the electron beam. Such velocity tapering is achieved in the present invention by varying the resonant frequency of the coupling elements coupling adjacent cavities of the slow wave structure in accordance with a predetermined tapering law so that the resonant frequency of the coupling elements towards the output end of the tube approaches the resonant frequency of the cavities.
Inventors
- 👤 R King
- 👤 N Harris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:01
CPC Classifications
H; H01; H01J; H01J25/00; H01J25/34; H01J25/36; H01J25/38
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
171 words
A travelling wave tube including an electron gun for producing an electron beam; a collector electrode for collecting said electron beam; a coupled cavity slow wave structure between said gun and collector for coupling radio frequency energy into and out of said electron beam and having a pass band defining a predetermined center frequency; a radio frequency signal input adjacent said electron gun and coupled to said slow wave structure to feed thereto radio frequency signals to be coupled to the beam; and a radio frequency signal output adjacent said collector electrode and coUpled to the slow wave structure for extracting amplified radio frequency signals therefrom; and in which tube adjacent cavities of the slow wave structure are coupled one to the other by resonant coupling elements, the resonant frequencies of which elements are different from said center frequency and the resonant frequencies of some of which elements at the output end of the structure change successively to approach said center frequency toward the radio frequency output end of the tube.
Claim 2
Dependent Claim
171 words
A travelling wave tube including an electron gun for producing an electron beam; a collector electrode for collecting said electron beam; a coupled cavity slow wave structure between said gun and collector for coupling radio frequency energy into and out of said electron beam and having a pass band defining a predetermined center frequency; a radio frequency signal input adjacent said electron gun and coupled to said slow wave structure to feed thereto radio frequency signals to be coupled to the beam; and a radio frequency signal output adjacent said collector electrode and coUpled to the slow wave structure for extracting amplified radio frequency signals therefrom; and in which tube adjacent cavities of the slow wave structure are coupled one to the other by resonant coupling elements, the resonant frequencies of which elements are different from said center frequency and the resonant frequencies of some of which elements at the output end of the structure change successively to approach said center frequency toward the radio frequency output end of the tube.
Claim 3
Dependent Claim
41 words
A travelling wave tube as claimed in claim 1 wherein said change of coupling elements'' resonant frequency is in accordance with a linear law such that the difference in resonant frequencies between successive elements of said some elements is the same.
Claim 4
Dependent Claim
50 words
A travelling wave tube as claimed in claim 1 wherein the resonant elements are slots in common partition walls between the cavities which slots forming said some elements vary in length from one partition wall to the next towards the output end so as successively to decrease their resonant frequency.
Claim 5
Dependent Claim
43 words
A travelling wave tube as claimed in claim 3 wherein the slot coupled structure is of the ''''clover leaf'''' type with radial slots and in which the slot length is increased to decrease the resonant frequency toward the output end of the tube.
Claim 6
Dependent Claim
42 words
A travelling wave tube as claimed in claim 3 wherein the slot coupled structure is of the harmonic interaction kind with circumferential slots in which the slot length is increased to decrease the resonant frequency toward the output end of the tube.
Claim 7
Dependent Claim
53 words
A travelling wave tube as claimed in claim 1 wherein the slot coupled structure is of the inverted kind so that the resonant frequencies of said elements are less than said center frequency and in which the slot length is decreased to increase the resonant frequency toward the output end of the tube.
Claim 8
Dependent Claim
64 words
A travelling wave tube as claimed in claim 3 wherein the cavities are loop coupled, by a structure such as a ''''centipede'''' structure known per se in which the coupling elements are ''''S'''' shaped loops in common partition walls between the cavities and in which the circumferential spacing between the loops is decreased to provide a reduction in the resonant frequency of the elements.
Claim 9
Dependent Claim
61 words
A travelling wave tube as claimed in claim 3 wherein the cavities are loop coupled, by a structure such as a ''''centipede'''' structure known per se in which the coupling elements are ''''S'''' shaped loops in common partition walls between the cavities and in which the loop amplitude is increased to provide a reduction in the resonant frequency of the elements.
Claim 10
Dependent Claim
44 words
A travelling wave tube as claimed in claim 3 wherein the resonant frequency of said elements is used to provide only a part of the total required ''''velocity taper'''' the remaining part being provided by variation of the cavity height at the output end.
Claim 11
Dependent Claim
30 words
A travelling wave tube as claimed in claim 1 wherein the height of the cavities is varied in accordance with a predetermined taper towards the output end of the tube.
References Cited (Backward Citations)
US3374390A
Cited
US3274428A
Cited
US3555462A
Cited
US3448326A
Cited
US3532924A
Cited
US3668459A
Cited
US3668460A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-04 | 1978-05-06 | 1978-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-04 | 1982-05-06 | 1982-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-04 | 1986-05-06 | 1986-11-05 | $7700.00 | Window Closed / Lapsed |