EP2034507A1 - Amplificateur à large bande pour tube à ondes progressives et son procédé de fabrication - Google Patents
Amplificateur à large bande pour tube à ondes progressives et son procédé de fabrication Download PDFInfo
- Publication number
- EP2034507A1 EP2034507A1 EP07425554A EP07425554A EP2034507A1 EP 2034507 A1 EP2034507 A1 EP 2034507A1 EP 07425554 A EP07425554 A EP 07425554A EP 07425554 A EP07425554 A EP 07425554A EP 2034507 A1 EP2034507 A1 EP 2034507A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- casing
- longitudinal projections
- amplifier
- slow
- supports
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- 239000004020 conductor Substances 0.000 claims abstract description 8
- 238000000034 method Methods 0.000 claims description 18
- 239000000463 material Substances 0.000 claims description 7
- 238000009760 electrical discharge machining Methods 0.000 claims description 4
- 239000003989 dielectric material Substances 0.000 claims description 3
- 230000008569 process Effects 0.000 claims description 3
- 238000005498 polishing Methods 0.000 claims 2
- 239000006185 dispersion Substances 0.000 description 4
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- 238000010894 electron beam technology Methods 0.000 description 3
- 230000003993 interaction Effects 0.000 description 3
- 238000003754 machining Methods 0.000 description 3
- 238000001465 metallisation Methods 0.000 description 2
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- LTPBRCUWZOMYOC-UHFFFAOYSA-N beryllium oxide Inorganic materials O=[Be] LTPBRCUWZOMYOC-UHFFFAOYSA-N 0.000 description 1
- 238000005219 brazing Methods 0.000 description 1
- 230000000711 cancerogenic effect Effects 0.000 description 1
- 231100000315 carcinogenic Toxicity 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
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- 238000005859 coupling reaction Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
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- 238000002347 injection Methods 0.000 description 1
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- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
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Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
- H01J23/12—Vessels; Containers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
- H01J23/16—Circuit elements, having distributed capacitance and inductance, structurally associated with the tube and interacting with the discharge
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
- H01J23/16—Circuit elements, having distributed capacitance and inductance, structurally associated with the tube and interacting with the discharge
- H01J23/165—Manufacturing processes or apparatus therefore
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
- H01J25/34—Travelling-wave tubes; Tubes in which a travelling wave is simulated at spaced gaps
Definitions
- the present invention relates to a travelling-wave-tube wide-band amplifier and to a corresponding method of fabrication.
- travelling-wave-tube wide-band (TWT-WB) amplifiers are used in the telecommunications sector for processing large amounts of information at a high frequency (in particular, in the bands C, X, Ku, between 4 and 18 GHz approximately).
- a helical TWT amplifier 1 comprises a substantially cylindrical conductive casing 2, in which a vacuum is formed, and a slow-wave helical structure 3, coaxial to the outer casing.
- the slow-wave structure 3 is kept in position by dielectric supports 5, which extend in a radial direction between the slow-wave structure 3 itself and a cylindrical internal surface of the casing 2. According to a configuration that is prevalently adopted, three dielectric supports 5 are used, spaced at uniform angular distances apart.
- an electron beam is injected along the axis of the slow-wave structure 3, in which the radiofrequency electromagnetic signals to be amplified are also injected.
- the slow-wave structure 3 is shaped so that the phase velocity of the electromagnetic signals according to the axis of the amplifier is reduced until it is comparable with the speed of the electron flow, enabling interaction between the electromagnetic signals themselves and the electron beam. Following upon said interaction, the electrons are decelerated and transfer energy to the electromagnetic signals, which are thus amplified.
- phase velocity can vary also to the extent of 10% and above.
- vanes 7 plane conductive laminae (commonly referred to as "vanes") 7, fixed to the internal surface of the casing 2.
- the vanes 7 develop mainly in a longitudinal direction and moreover extend radially from the internal surface of the casing 2 towards the axis of the TWT amplifier 1.
- the presence of the vanes 7 has a prevalent effect on the electrical field of the electromagnetic wave in the lower part of the frequency band of use (capacitive effect).
- the vanes 7 reduce significantly the dependence of the phase velocity upon the frequency, thereby determining a reduction in the radiofrequency gain of the TWT amplifier. It is in practice possible to make TWT amplifiers that operate in a satisfactory way on the entire band of use.
- vanes are in fact long and thin, and fixing thereof to the internal surface of the casing, which is normally performed by brazing, is critical.
- the length of the vanes may in fact be also hundreds or thousands of times greater than the width (tens of centimetres as against tenths of a millimetre).
- the precision of the operations of mounting is then hard to control, and, since the vanes are very liable to damage, the risk of producing defective pieces is somewhat high.
- the assembly of the vanes entails long times and is expensive.
- the aim of the present invention is to provide a travelling-wave-tube amplifier and a method of fabrication of a travelling-wave-tube amplifier that are free from the drawbacks described and, in particular, enable a reduction in the dependence of the phase velocity upon the frequency and, at the same time, are simple to produce.
- a travelling-wave-tube amplifier and a method of fabrication of a travelling-wave-tube amplifier are provided, as defined in Claims 1 and 11, respectively.
- a travelling-wave-tube amplifier or TWT amplifier 10 comprises: an amplifier tube 11, which extends along an axis A; an electron gun 12; a collector 13; an input-signal coupler 15; and an output-signal coupler 16.
- the electron gun 12 is coupled to one end of the amplifier tube 11 for emitting, in use, a beam of electrons focused substantially along the axis A of the amplifier tube 11, in which the vacuum is created.
- a permanent-periodic-magnet (PPM) structure is present, (known and not illustrated herein).
- the collector 13 is located at an opposite end of the amplifier tube 11 for receiving the electrons coming from the electron gun 12.
- the input-signal coupler 15 and the output-signal coupler 16 are arranged in the proximity of the electron gun 12 and of the collector 13 and enable, respectively, injection of a low-power input signal SIN into the amplifier tube 11 and picking-up of an amplified output signal SOUT.
- the amplifier tube 11 comprises a casing 18 and a slow-wave helical structure 20, which is coaxial with, and is aligned to, the axis A.
- the casing 18 is made of conductive material and is externally cylindrical and hollow. Internally, the casing 18 has first portions of cylindrical surface 18a, having a first radius R1, and longitudinal projections 18b, which extend parallel to the axis A and are projected radially for a stretch towards the slow-wave structure 20 from the portions of cylindrical surface 18a. In the embodiment herein described, three longitudinal projections 18b are present, spaced at uniform angular distances apart.
- the longitudinal projections 18b are made of a single piece with the rest of the casing 18, of the same conductive material and in cross section are shaped like the capital of a column. More precisely, the longitudinal projections 18b are delimited radially by respective second portions of cylindrical surface 18c having a second radius R2 smaller than the first radius R1.
- the slow-wave structure 20 is defined by a conductor wound in a helix about the axis A with a third pre-determined external radius R3 and is kept in position by supports 22 of dielectric material, which rest directly against respective longitudinal projections 18b (the supports 22 are as many as the longitudinal projections 18b).
- the longitudinal projections 18b have larger widths than the supports 22 so as to provide a convenient resting base.
- the supports are approximately 0.6 mm wide, whilst the width of the longitudinal projections 18b is approximately 1.4 mm.
- the ratio between a radial dimension of the longitudinal projections 18b and a radial dimension of the supports 22 is preferably approximately 0.5 mm.
- the radial dimension of the longitudinal projections 18b is equal to the difference R1 - R2 between the first radius R1 and the second radius R2.
- the radial dimension of the supports 22 is substantially equal to the difference R2 - R3 between the second radius R2 and the third radius R3 of the slow-wave structure 20.
- the conformation of the longitudinal projections 18b enables excellent results to be achieved as regards the reduction of the dependence of the phase velocity upon the frequency, which can be brought down even below 3% on the entire band of operation (for example, from 5 GHz to 15 GHz).
- the fabrication and the assembly are considerably simplified, as will be clarified in what follows, with reference to Figures 6-9 .
- the surface that delimits the through cavity 26 is then subjected to a lapping process, to minimize the roughness. In this way, the thermal coupling with the supports 22, once these have been installed, is optimal.
- the longitudinal projections 18b are made by removal of material starting from the bored ingot 25, in particular by electrical-discharge machining (EDM), for example wire-EDM.
- EDM electrical-discharge machining
- the internal surface of the ingot 25 is machined locally by removing portions of material (dashed line in Figure 7 ) to form recesses that separate the longitudinal projections 18b.
- the machining proceeds until the first portions of cylindrical surface 18a having the first radius R1 are defined.
- the casing 18 is thus obtained starting from the cylindrical ingot 25.
- the slow-wave structure 20 and the pre-assembled supports 22 are introduced within the casing 18, as illustrated in Figure 9 , so that the supports 22 slide along the second cylindrical surfaces 18c of the longitudinal projections 18b. Correct position of the slow-wave structure 20 and of the supports 22 within the casing 18 is ensured by a pre-determined interference.
- the amplifier tube 11 is then completed in a conventional way with the mounting of the electron gun 12, the collector 13, the input-signal coupler 15, and the output-signal coupler 16.
- the amplifier according to the invention and the corresponding method of fabrication have different advantages.
- the longitudinal projections 18b In first place, it is possible to obtain an optimal reduction of the dispersion of the phase velocity, without using the conventional longitudinal vanes.
- the longitudinal projections 18b albeit having a different conformation, obtain the same effect as the vanes on the interaction between the electron beam flowing along the axis A and the radio-frequency electromagnetic signals that travel on the slow-wave structure 20.
- the construction of the longitudinal projections 18b, made of a single piece with the casing 18, is, however, much simpler and does not entail complex assembly operations. It is possible to use extremely accurate and reliable machining techniques, such as for example EDM.
- the longitudinal projections 18b could in any case be obtained also with other techniques, for example by precision-milling.
- the longitudinal projections 18b do not suffer from the intrinsic structural brittleness of the vanes, so that the risk of damage during machining is practically inexistent.
- the method of fabrication is thus substantially simplified, fast, and has a high yield.
- the interface between the supports 22 and the longitudinal projections 18b is moreover treated by lapping and thus offers the maximum surface of heat exchange, further favouring the dispersion of heat.
- the longitudinal projections and the dielectric supports could have shapes and proportions different from the ones described and illustrated herein.
- the longitudinal projections could have the same width as the supports.
- the radial dimensions and their ratio could be different.
- the number of the longitudinal projections and of the supports could be different (for example, there could be present four longitudinal projections and as many supports).
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Microwave Tubes (AREA)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP07425554A EP2034507A1 (fr) | 2007-09-07 | 2007-09-07 | Amplificateur à large bande pour tube à ondes progressives et son procédé de fabrication |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP07425554A EP2034507A1 (fr) | 2007-09-07 | 2007-09-07 | Amplificateur à large bande pour tube à ondes progressives et son procédé de fabrication |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP2034507A1 true EP2034507A1 (fr) | 2009-03-11 |
Family
ID=39262816
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP07425554A Withdrawn EP2034507A1 (fr) | 2007-09-07 | 2007-09-07 | Amplificateur à large bande pour tube à ondes progressives et son procédé de fabrication |
Country Status (1)
| Country | Link |
|---|---|
| EP (1) | EP2034507A1 (fr) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114530359A (zh) * | 2022-02-22 | 2022-05-24 | 电子科技大学 | 一种同轴多通道悬置微带线慢波结构行波管 |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2887608A (en) * | 1954-04-29 | 1959-05-19 | Sperry Rand Corp | Travelling wave tube |
| US2948954A (en) * | 1956-03-08 | 1960-08-16 | Alexander P Ramsa | Small sized helixes and method of their fabrication |
| US3121819A (en) * | 1959-12-30 | 1964-02-18 | Itt | Arrangement for reducing high voltage breakdown between helical windings in traveling wave tubes |
| GB1070916A (en) * | 1964-07-03 | 1967-06-07 | Takeo Hukunaga | Electron discharge device having a slow wave structure |
| US3401298A (en) * | 1964-07-30 | 1968-09-10 | Gen Electric Co Ltd | Noise reduction in a travelling wave tube employing a helix input coupler |
| US3408529A (en) * | 1965-08-30 | 1968-10-29 | Westinghouse Electric Corp | Helical slow wave structure for a travelling wave tube to provide heat removal from the slow wave structure |
| GB1143251A (en) * | 1965-04-30 | 1969-02-19 | Varian Associates | Band-edge oscillation suppression techniques for high frequency electron discharge devices incorporating slow-wave circuits |
| US3540119A (en) * | 1968-02-19 | 1970-11-17 | Varian Associates | Method for fabricating microwave tubes employing helical slow wave circuits |
| GB2128111A (en) * | 1982-10-06 | 1984-04-26 | English Electric Valve Co Ltd | Improvements in or relating to coupled cavity travelling wave tubes |
-
2007
- 2007-09-07 EP EP07425554A patent/EP2034507A1/fr not_active Withdrawn
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2887608A (en) * | 1954-04-29 | 1959-05-19 | Sperry Rand Corp | Travelling wave tube |
| US2948954A (en) * | 1956-03-08 | 1960-08-16 | Alexander P Ramsa | Small sized helixes and method of their fabrication |
| US3121819A (en) * | 1959-12-30 | 1964-02-18 | Itt | Arrangement for reducing high voltage breakdown between helical windings in traveling wave tubes |
| GB1070916A (en) * | 1964-07-03 | 1967-06-07 | Takeo Hukunaga | Electron discharge device having a slow wave structure |
| US3401298A (en) * | 1964-07-30 | 1968-09-10 | Gen Electric Co Ltd | Noise reduction in a travelling wave tube employing a helix input coupler |
| GB1143251A (en) * | 1965-04-30 | 1969-02-19 | Varian Associates | Band-edge oscillation suppression techniques for high frequency electron discharge devices incorporating slow-wave circuits |
| US3408529A (en) * | 1965-08-30 | 1968-10-29 | Westinghouse Electric Corp | Helical slow wave structure for a travelling wave tube to provide heat removal from the slow wave structure |
| US3540119A (en) * | 1968-02-19 | 1970-11-17 | Varian Associates | Method for fabricating microwave tubes employing helical slow wave circuits |
| GB2128111A (en) * | 1982-10-06 | 1984-04-26 | English Electric Valve Co Ltd | Improvements in or relating to coupled cavity travelling wave tubes |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114530359A (zh) * | 2022-02-22 | 2022-05-24 | 电子科技大学 | 一种同轴多通道悬置微带线慢波结构行波管 |
| CN114530359B (zh) * | 2022-02-22 | 2023-04-18 | 电子科技大学 | 一种同轴多通道悬置微带线慢波结构行波管 |
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