US3903449A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Anisotropic shell loading of high power helix traveling wave tubes
Assignee: Varian Medical Systems Inc
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Filing: 1974-06-13
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Granted: 1975-09-02
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Expires: 1994-06-13
Abstract
Abstract The helix of a high power traveling wave tube, i.e., in excess of ten watts cw, is supported from a thermally conductive barrelshaped metallic envelope via the intermediary of a plurality of beryllia or boron nitride rods disposed at circumferentially spaced locations around the periphery of the helix. The helix is anisotropically loaded for decreasing the positive dispersion or, in the alternative, producing a negative dispersion characteristic by means of a loading structure disposed surrounding the helix intermediate the helix and the barrel structure. In one embodiment, the loading structure comprises a plurality of arcuate quartz sectors having an array of longitudinally directed electrically conductive elements supported on the inside surface thereof adjacent the helix. In a second embodiment, the loading structure comprises a plurality of arcuate alumina sectors interposed between the helix and the surrounding barrel structure. These loading elements of both types greatly increase the operating bandwidth over which relatively high gain and efficiency are obtainable.
Inventors
- 👤 Allan W Scott
- 👤 Ernest A Conquest
- 👤 John L Putz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:03
CPC Classifications
H; H01; H01J; H01J23/00; H01J23/16; H01J23/24; H01J23/26
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
170 words
In a high power traveling wave tube: a vacuum envelope; means for producing a stream of electrons; a helix type radio frequency slow wave interaction circuit disposed along the path of said stream of electrons in radio frequency energy exchanging relation therewith; a generally cylindrical metallic shell surrounding said interaction circuit; a plurality of dielectric support means circumferentially spaced around said interaction circuit, extending along said circuit and supporting said circuit from said shell; anisotropic loading means interposed between said circuit and said shell for making more negative the dispersion characteristic of said circuit; said anisotropic loading means comprising a plurality of dielectric sectors extending lengthwise of said circuit, circumferentially disposed between said dielectric support means, and abutting said metallic shell; said dielectric sectors having, a dielectric constant between 9.0 and 10.0, an inner radius from the center of said circuit within the range of 1.3 to 1.4 times the mean radius of said circuit, and an outer radius within 2.0 to 3.0 times said mean radius of said circuit.
Claim 2
Dependent Claim
170 words
In a high power traveling wave tube: a vacuum envelope; means for producing a stream of electrons; a helix type radio frequency slow wave interaction circuit disposed along the path of said stream of electrons in radio frequency energy exchanging relation therewith; a generally cylindrical metallic shell surrounding said interaction circuit; a plurality of dielectric support means circumferentially spaced around said interaction circuit, extending along said circuit and supporting said circuit from said shell; anisotropic loading means interposed between said circuit and said shell for making more negative the dispersion characteristic of said circuit; said anisotropic loading means comprising a plurality of dielectric sectors extending lengthwise of said circuit, circumferentially disposed between said dielectric support means, and abutting said metallic shell; said dielectric sectors having, a dielectric constant between 9.0 and 10.0, an inner radius from the center of said circuit within the range of 1.3 to 1.4 times the mean radius of said circuit, and an outer radius within 2.0 to 3.0 times said mean radius of said circuit.
Claim 3
Dependent Claim
214 words
In a high power traveling wave tube: means for producing a stream of electrons; a helix radio frequency slow wave interaction circuit disposed along the path of said stream of electrons in radio frequency energy exchanging relation therewith for cumulative stream-field interaction with the stream to produce a growing radio frequence wave on said circuit; an evacuated envelope structure having a metallic portion surrounding said interaction circuit; dielectric support means circumferentially spaced apart around said helix slow wave circuit and extending along said circuit for supporting said helix from said envelope in electrically insulative and heat exchange relation therewith; and anisotropic loading means surrounding said helix radio frequency interaction circuit and being interposed between said envelope and said helix for adding a negative dispersion effect to the normal positive dispersion characteristic of said helix slow wave circuit, thereby obtaining a less positive or more negative disPersion characteristic, said loading means comprising a plurality of elongated arcuate dielectric support sectors extending along the length of said helix slow wave circuit, said support sectors including an array of elongated longitudinally directed circumferentially spaced electric conductors formed on the inner face thereof facing said helix slow wave circuit, said array of conductors surrounding said helix and being supported from the inner face of said arcuate dielectric sectors.
Claim 4
Dependent Claim
214 words
In a high power traveling wave tube: means for producing a stream of electrons; a helix radio frequency slow wave interaction circuit disposed along the path of said stream of electrons in radio frequency energy exchanging relation therewith for cumulative stream-field interaction with the stream to produce a growing radio frequence wave on said circuit; an evacuated envelope structure having a metallic portion surrounding said interaction circuit; dielectric support means circumferentially spaced apart around said helix slow wave circuit and extending along said circuit for supporting said helix from said envelope in electrically insulative and heat exchange relation therewith; and anisotropic loading means surrounding said helix radio frequency interaction circuit and being interposed between said envelope and said helix for adding a negative dispersion effect to the normal positive dispersion characteristic of said helix slow wave circuit, thereby obtaining a less positive or more negative disPersion characteristic, said loading means comprising a plurality of elongated arcuate dielectric support sectors extending along the length of said helix slow wave circuit, said support sectors including an array of elongated longitudinally directed circumferentially spaced electric conductors formed on the inner face thereof facing said helix slow wave circuit, said array of conductors surrounding said helix and being supported from the inner face of said arcuate dielectric sectors.
Claim 5
Dependent Claim
19 words
The apparatus of claim 2 wherein said dielectric support sectors which support said array of conductors are of quartz.
Claim 6
Dependent Claim
32 words
The apparatus of claim 2 wherein said array of elongated longitudinally directed conductors are axially coextensive with said helix along at least 90% of the length of said helix slow wave circuit.
Claim 7
Dependent Claim
33 words
The apparatus of claim 2 wherein the ratio of the inside diameter of said array of electrical conductors to the mean diameter to said helix falls within the range of 1.3 to 1.4.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |