US3811065A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Velocity modulation microwave tube employing a harmonic prebuncher for improved efficiency
Assignee: Varian Medical Systems Inc
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Filing: 1973-02-14
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Granted: 1974-05-14
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Expires: 1993-02-14
Abstract
Abstract The velocity modulation microwave tube includes an electron gun for projecting a stream of electrons over an elongated beam path to a collector structure. An input circuit and an output circuit are disposed at the upstream and downstream ends, respectively, of the beam for applying microwave energy to be amplified to the tube and for extracting the amplified microwave energy from the beam. A penultimate resonator circuit, tuned for a mode of resonance at a frequency near the passband of the tube, is provided just upstream of the output circuit for bunching the current density of the beam passing into the output circuit. A harmonic floating resonator structure is disclosed along the beam path intermediate the input circuit and the penultimate resonator. The harmonic resonator is tuned for a mode of resonance approximately at a frequency corresponding to a harmonic higher than the first of the center frequency of the passband of the tube. The harmonic resonator serves as a prebuncher to bunching the electrons of the beam prior to their entering the final stage of bunching performed by the penultimate floating resonator. The combined action of the harmonic prebuncher resonator and the penultimate final buncher resonator is to substantially increase the radio frequency conversion efficiency of the tube.
Inventors
- 👤 E Lien
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:20
CPC Classifications
H; H01; H01J; H01J25/00; H01J25/02; H01J25/10; H01J25/20
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
216 words
In a velocity modulation microwave tube apparatus having a certain operating passband of frequencies, means for projecting a stream of electrons over an elongated beam path, means forming a plurality of wave supportive structures arranged successively along the beam path for successive electromagnetic interaction with the electron stream to produce output microwave energy, said plurality of wave supportive structures including an input circuit, an output circuit, and a penultimate resonator circuit, said penultimate resonator circuit being tuned for a mode of resonance at a frequency above the passband of the tube, the frequency of said fundamental mode of resonance being less than twice the center passband frequency, said penultimate resonator circuit comprising at least one floating resonator for bunching the beam passing into said output circuit, the improvement comprising, means forming a harmonic floating resonator structure disposed along the beam path intermediate said input circuit and said penultimate resonator circuit, said harmonic resonator having a mode of resonance approximately at a frequency corresponding to a harmonic which is an integral multiple of the center frequency of the passband of the tube, whereby the electrons of the beam are prebunched by said harmonic resonator prior to their entering the final stage of bunching performed by said penultimate resonator circuit to improve the conversion efficiency of the tube.
Claim 2
Dependent Claim
216 words
In a velocity modulation microwave tube apparatus having a certain operating passband of frequencies, means for projecting a stream of electrons over an elongated beam path, means forming a plurality of wave supportive structures arranged successively along the beam path for successive electromagnetic interaction with the electron stream to produce output microwave energy, said plurality of wave supportive structures including an input circuit, an output circuit, and a penultimate resonator circuit, said penultimate resonator circuit being tuned for a mode of resonance at a frequency above the passband of the tube, the frequency of said fundamental mode of resonance being less than twice the center passband frequency, said penultimate resonator circuit comprising at least one floating resonator for bunching the beam passing into said output circuit, the improvement comprising, means forming a harmonic floating resonator structure disposed along the beam path intermediate said input circuit and said penultimate resonator circuit, said harmonic resonator having a mode of resonance approximately at a frequency corresponding to a harmonic which is an integral multiple of the center frequency of the passband of the tube, whereby the electrons of the beam are prebunched by said harmonic resonator prior to their entering the final stage of bunching performed by said penultimate resonator circuit to improve the conversion efficiency of the tube.
Claim 3
Dependent Claim
32 words
The apparatus of claim 1 wherein said penultimate resonator circuit comprises more than one floating resonator tuned for a fundamental mode of resonance at a frequency above the passband of the tube.
Claim 4
Dependent Claim
12 words
The apparatus of claim 1 wherein said resonators are re-entrant cavity resonators.
Claim 5
Dependent Claim
30 words
The apparatus of claim 1 wherein said harmonic resonator is tuned for a mode of resonance approximately at the second harmonic at the center of the passband of the tube.
Claim 6
Dependent Claim
37 words
The apparatus of claim 1 wherein a second one of said harmonic resonators is arranged along the beam path intermediate said input circuit and said penultimate resonator circuit for further increasing the conversion efficiency of the tube.
Claim 7
Dependent Claim
17 words
The apparatus of claim 1 wherein the beam has a perveance greater than 0.1 X 10 6.
Claim 8
Dependent Claim
49 words
The apparatus of claim 1 wherein the harmonic resonator is tuned to a frequency lower than the certain higher harmonic of the center of the passband of the tube, and said penultimate resonator circuit is tuned to a frequency higher than the center of the passband of the tube.
Claim 9
Dependent Claim
23 words
The apparatus of claim 2 wherein said floating resonators are tuned to frequencies higher than the center of the passband of the tube.
Claim 10
Dependent Claim
39 words
The apparatus of claim 1 wherein more than one said harmonic resonator is arranged along the beam path intermediate said input circuit and said penultimate resonator circuit and wherein said penultimate resonator circuit comprises more than one floating resonator.
Claim 11
Dependent Claim
51 words
The apparatus of claim 9 wherein said harmonic resonators are tuned to frequencies lower than the certain higher harmonic of the center of the passband of the tube and said floating resonators of said penultimate resonator circuit are tuned to frequencies higher than the center of the passband of the tube.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-13 | 1977-11-12 | 1978-05-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-13 | 1981-11-12 | 1982-05-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-13 | 1985-11-12 | 1986-05-14 | $7700.00 | Window Closed / Lapsed |