US2880120A - Method of manufacturing a microwave attenuator for travelling wave tube - Google Patents

Method of manufacturing a microwave attenuator for travelling wave tube Download PDF

Info

Publication number
US2880120A
US2880120A US427439A US42743954A US2880120A US 2880120 A US2880120 A US 2880120A US 427439 A US427439 A US 427439A US 42743954 A US42743954 A US 42743954A US 2880120 A US2880120 A US 2880120A
Authority
US
United States
Prior art keywords
rod
travelling wave
helix
attenuator
wave tube
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.)
Expired - Lifetime
Application number
US427439A
Other languages
English (en)
Inventor
James S Pelle
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Unisys Corp
Original Assignee
Sperry Rand Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to NL93132D priority Critical patent/NL93132C/xx
Priority to NL196805D priority patent/NL196805A/xx
Application filed by Sperry Rand Corp filed Critical Sperry Rand Corp
Priority to US427439A priority patent/US2880120A/en
Priority to GB10641/55A priority patent/GB770083A/en
Priority to FR1131125D priority patent/FR1131125A/fr
Priority to DES43808A priority patent/DE1013732B/de
Application granted granted Critical
Publication of US2880120A publication Critical patent/US2880120A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/009—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone characterised by the material treated
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
    • C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
    • C04B41/5001—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials with carbon or carbonisable materials
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
    • C04B41/81—Coating or impregnation
    • C04B41/85—Coating or impregnation with inorganic materials
    • 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
    • H01J23/24—Slow-wave structures, e.g. delay systems
    • H01J23/30—Damping arrangements associated with slow-wave structures, e.g. for suppression of unwanted oscillations
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2913—Rod, strand, filament or fiber
    • Y10T428/2918—Rod, strand, filament or fiber including free carbon or carbide or therewith [not as steel]
    • Y10T428/292—In coating or impregnation

Definitions

  • This invention relates to microwave attenuators, and more particularly, is concerned with the method of making attenuatingsupportrods for the helix transmission line of a high-power travelling wave tube.
  • the rods are of a material such as glass or ceramic and the coating is colloidal graphite of particular thickness and distribution along. the rods for controlling the attenuation properties thereof.
  • An alternative to the colloidal graphite coating has been theme of a vaporized metal film, the resistance being controlled by the density of the film.
  • the metal film attenuators have proved disadvantageous for high-power applications for the reasons that the vaporizing of the coating on the surface of the rods is too critical and elaborate" to I obtain easyt reproducibility. Because of thethinness Oflhefllmplt is easily scratched or otherwise damaged. Furthermore, any metal film which can be readily vaporized to provide such a coating is not stable when raised to temperatures encountered in tubes at high-power operation. The metal, having a high surface tension, tends to collect in globules when subjected to repeated heating to elevated temperatures, so that the attenuating propertiesof thefilm are destroyed with use. Even far below melting temperatures, such thin metal layers difiuse from high power attenuation regions 2,880,120 Patented Mar. 31, 1959 ice 2 (high temperatures) to low power regions (low temperatures), and thus the attenuation is destroyed.
  • Another object of this invention is to provide an attenuating material which can be used in the formof elongated rods for serving the dual purpose of supporting 'the helix of a travelling wave'tube and providing the'requir'ed attenuation for improved operation of the tube.
  • Another object of this invention is the provision of an attenuator in which the amount of attenuation per unit length can be readily controlled.
  • Another object of this invention is to provide an attenuator in which microwave attenuation takes place throughout the volume of the attenuator rather than only at the surface, so that the attenuating. properties are not aifected by marring or scratching or other injury occurring at the surface of the attenuator.
  • an attenuator consisting of a material produced in the following manner.
  • Aporous ceramicrod of proper length and diameter to serve as a'helix" sup.- port rod in a travelling wave tube is soaked in a solution of sucrose and water.
  • the rod is thendried to remove the excess water and heatedfor fifteen minutes at 400 C. in an inert atmosphere or inits own vapors of decomposition, thus changing the sucrose to colloidal carbon deposited in the pores of the ceramic rod;
  • The'rod is then fired in a vacuum for a proper period of time at an elevated temperature of 1000 C., in which process colloidal carbon is converted to graphite.
  • the amount of sucrose material and the degree and time of firing in converting the carbon to graphite determine the resistance and attenuating properties of the rod.
  • Fig. 1 is an elevational view, partly in section, of a travelling wave tube embodying the present invention
  • Fig. 2 is a fragmentary cross-sectional view taken on the line 22of Fig. 1
  • Fig. 3 is an enlarged view of'the attenuating rods and associated supporting structure of the tube illustrated in Fig. 1';
  • Fig. 4 is a flow diagram illustrating'the steps in the preparation of the attenuator rods of the present invention.
  • the numeral 10 indicates generally a travelling wave tube of a type described'in detail in the copending application Serial No. 426,323, filed April'29, 1954.
  • Thetravelling wave tube includes an outer shell 10 of conductive non-magnetic material with an electron gun asserhbly 14 positioned at one end and a collector 16 positioned at the opposite end. Extending axially through the tube is a helical conductor 18 supported along its length by a plurality of rods 20. Sections of coaxial transmission lines, indicated generally at 22 and 24, couple the RF. signal amplified by the tube respectively into and out of the helix transmission line 18.
  • A-horn member 26 is positioned within the tube adjacent the electron gun assembly 14.
  • a central flaring opening 28 coaxial with the helix 18 receives the end of the helix.
  • the support rods 20 are received in bores3j0 in the horn member, the rods being supported and accurately positioned thereby.
  • the coaxial line 22 is coupled to the end of the helix within the flaring opening 28.
  • a second horn member 32 is similarly positioned at the opposite end of the helix 18 and supports the rods 20.
  • Fig. 3 shows the assembly of the rods 20 and supporting members 26 and 32 at each end.
  • the attenuating rods 20, which are made in the manner of the present invention, are in contact with the helix around the outer periphery thereof.
  • the rods are in a position to attenuate fields external to the helix and at the same time give mechanical support to the helix.
  • the attenuating rods 20 are prepared in the following manner, as indicated in the flow diagram of Fig. 4.
  • a porous ceramic rod of such material as aluminum silicate or magnesium silicate of proper length and shape is used.
  • An example of a suitable material is AI-222, American Lava Corporation of Tennessee.
  • the rod is soaked in a 40% solution by weight of sucrose and water and dried. However, the solution may be brushed on so as to limit the portion of the rod in which the solution is applied. Where soaking is used, it may be desirable to coat portions of the rod with parafiin in the regions where it is desired not to have attenuation.
  • the attenuating properties of the rod may be confined to the central region of the rods, as indicated at 34 in Fig. 3. While a 40% solution is recommended for maximum effect, thinner solutions may be used where less attenuation is desired.
  • sucrose has been found highly satisfactory, other polyhydroxyl compounds may be employed providing they are not readily vaporized before decomposition to carbon sets in. All of the sugars, for example, glucose, lactose, dextrin and other polyhydroxyl compounds are satisfactory.
  • the rod After the rod is dried to remove the solvent, it is heated for at least fifteen minutes at 400 C. This heating is done either in an inert atmosphere or in a very confined space where the available oxygen is limited. As a result of the heating, the sucrose is decomposed driving off the volatile products and leaving behind a precipitate of colloidal carbon. The process of soaking and heating may be repeated two or three additional times as may be required to precipitate the desired amount of carbon in the pores of the ceramic.
  • the ceramic rod After precipitating the colloidal carbon, the ceramic rod is then brought to proper resistance range by firing in an oxygen free atmosphere such as a vacuum or dry H atmosphere for at least ten minutes at 1000 C.
  • an oxygen free atmosphere such as a vacuum or dry H atmosphere for at least ten minutes at 1000 C.
  • the firing process reduces the colloidal carbon to graphite.
  • the ultimate resistance of the rod per unit length may be controlled by the length of time and the temperature at which the firing of the rod takes place.
  • the various objects of the invention have been achieved by the provision of an improved microwave attenuator. Since the attenuator may be operated at high temperatures for a sustained period, it is particularly suited for high-power applications. Although the form of the attenuator has been described as a rod for use in a travelling wave tube, it will be recognized that the attenuating material produced by the above-described process may be adapted for other uses, for example, as a non-reflecting dissipative load for a microwave transmission line and similar applications. The attenuator is particularly suitable for operation within a vacuum since none of the materials involved in the final product have a high vapor pressure. Where the attenuator is to be operated at red heat, it should be used in an inert atmosphere or in a vacuum to prevent oxidation of the carbon.
  • the method of manufacturing a microwave attenuator and support for the helix of a travelling wave tube comprising the steps of: impregnating part of a porous ceramic rod with a solution of an organic compound, heating said rod at a low temperature for gradual decomposition of said organic compound into a carbon containing material, and firing said rod at an elevated temperature well above said low temperature for converting said material to graphite having desired microwave loss properties.
  • the method of manufacturing a microwave attenuator and support for the helix of a travelling wave tube comprising the steps of: impregnating part of a porous ceramic rod with a solution of an organic compound, drying said rod, heating said rod in an inert atmosphere at a low temperature for gradual decomposition of said organic compound into a carbon containing material, and firing said rod in an oxygen free atmosphere at an elevated temperature well above said low temperature for converting said material to graphite having desired microwave loss properties.
  • the method of manufacturing a microwave attenuator and support for the helix of a travelling wave tube comprising the steps of: impregnating part of a porous ceramic rod with a sugar solution, drying the ceramic rod for evaporating the solvent of said solution, heating the rod in an inert atmosphere at a low temperature for a period of time sufiicient to partially decompose the sugar impregnated in said rod and produce a precipitate of col- Ioidal carbon in the pores of said rod, and firing the ceramic rod in an oxygen free atmosphere at an elevated temperature well above said low temperature for converting said colloidal carbon to graphite having desired microwave loss properties.
  • the method of manufacturing a microwave attenuator and support for the helix of a travelling wave tube comprising the steps of: impregnating part of a porous ceramic rod with a sugar solution, drying the ceramic rod in air for evaporating the solvent from said solution, heatmg the rod in an inert atmosphere at a low temperature below the order of 400 C. for a period of time sufiicient to partially decompose the sugar impregnated in said rod and produce a precipitate of colloidal carbon in the pores of said rod, and firing said rod in an oxygen free atmosphere at an elevated temperature of the order of 1000 C. for converting said colloidal carbon to graphite having desired microwave loss properties.
  • the method of producing a structure suitable for absorbing microwave energy comprising the steps of: impregnating a porous ceramic body with a solution of an organic compound, heating said body at a low temperature for gradual decomposition of said organic compound into a carbon containing material, and firing said body at an elevated temperature well above said low temperature for converting said material to graphite having desired microwave loss properties.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Microwave Tubes (AREA)
  • Ceramic Products (AREA)
  • Manufacturing Of Tubular Articles Or Embedded Moulded Articles (AREA)
  • Chemically Coating (AREA)
US427439A 1954-05-04 1954-05-04 Method of manufacturing a microwave attenuator for travelling wave tube Expired - Lifetime US2880120A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
NL93132D NL93132C (en(2012)) 1954-05-04
NL196805D NL196805A (en(2012)) 1954-05-04
US427439A US2880120A (en) 1954-05-04 1954-05-04 Method of manufacturing a microwave attenuator for travelling wave tube
GB10641/55A GB770083A (en) 1954-05-04 1955-04-13 Microwave attenuators and methods of their manufacture and travelling wave tubes incorporating such attenuators
FR1131125D FR1131125A (fr) 1954-05-04 1955-04-18 Atténuateur d'hyperfréquences pour tubes à ondes progressives
DES43808A DE1013732B (de) 1954-05-04 1955-05-04 Verfahren zur Herstellung eines Mikrowellendaempfungswiderstandes aus einem poroesen keramischen Stoff

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US427439A US2880120A (en) 1954-05-04 1954-05-04 Method of manufacturing a microwave attenuator for travelling wave tube

Publications (1)

Publication Number Publication Date
US2880120A true US2880120A (en) 1959-03-31

Family

ID=23694876

Family Applications (1)

Application Number Title Priority Date Filing Date
US427439A Expired - Lifetime US2880120A (en) 1954-05-04 1954-05-04 Method of manufacturing a microwave attenuator for travelling wave tube

Country Status (5)

Country Link
US (1) US2880120A (en(2012))
DE (1) DE1013732B (en(2012))
FR (1) FR1131125A (en(2012))
GB (1) GB770083A (en(2012))
NL (2) NL93132C (en(2012))

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3026214A (en) * 1957-12-13 1962-03-20 Gen Electric Co Ltd Process for production of low permeability carbon and resultant article
US3039897A (en) * 1958-04-09 1962-06-19 Robert W Waring Semiconductor and method of making the same
US3043040A (en) * 1957-09-06 1962-07-10 Silva Tony Christiano Method of transforming new bricks into bricks which simulate aged bricks
US3475707A (en) * 1966-12-21 1969-10-28 Varian Associates Porous intermediate layer for affixing lossy coatings to r.f. tube circuits
US3922383A (en) * 1974-02-28 1975-11-25 Universal Oil Prod Co Polymeric laminates
US5882726A (en) * 1996-01-02 1999-03-16 Msnw, Inc. Low-temperature densification of carbon fiber preforms by impregnation and pyrolysis of sugars
CN113620696A (zh) * 2021-08-05 2021-11-09 中国科学院福建物质结构研究所 低介电高损耗的氧化硅衰减陶瓷组合物、氧化硅衰减陶瓷及其制备方法和应用
CN116565496A (zh) * 2023-06-27 2023-08-08 济钢防务技术有限公司 一种螺旋线六方衰减器的制备方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2939993A (en) * 1957-01-07 1960-06-07 Gen Electric Traveling-wave tube attenuators

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1091616A (en) * 1911-03-13 1914-03-31 Gen Electric Graphite conductor.
US1745939A (en) * 1926-07-19 1930-02-04 Rca Corp Unalterable ohmic resistance
US2057431A (en) * 1933-03-29 1936-10-13 Raymond H Hobrock Method of making resistance elements
US2341219A (en) * 1940-12-06 1944-02-08 Owens Corning Fiberglass Corp Carbonaceous coating for glass fibers
US2487581A (en) * 1948-03-31 1949-11-08 Theodore R Palumbo Electrical resistor and method of making same
US2575383A (en) * 1946-10-22 1951-11-20 Bell Telephone Labor Inc High-frequency amplifying device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1091616A (en) * 1911-03-13 1914-03-31 Gen Electric Graphite conductor.
US1745939A (en) * 1926-07-19 1930-02-04 Rca Corp Unalterable ohmic resistance
US2057431A (en) * 1933-03-29 1936-10-13 Raymond H Hobrock Method of making resistance elements
US2341219A (en) * 1940-12-06 1944-02-08 Owens Corning Fiberglass Corp Carbonaceous coating for glass fibers
US2575383A (en) * 1946-10-22 1951-11-20 Bell Telephone Labor Inc High-frequency amplifying device
US2487581A (en) * 1948-03-31 1949-11-08 Theodore R Palumbo Electrical resistor and method of making same

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3043040A (en) * 1957-09-06 1962-07-10 Silva Tony Christiano Method of transforming new bricks into bricks which simulate aged bricks
US3026214A (en) * 1957-12-13 1962-03-20 Gen Electric Co Ltd Process for production of low permeability carbon and resultant article
US3039897A (en) * 1958-04-09 1962-06-19 Robert W Waring Semiconductor and method of making the same
US3475707A (en) * 1966-12-21 1969-10-28 Varian Associates Porous intermediate layer for affixing lossy coatings to r.f. tube circuits
DE1566028B1 (de) * 1966-12-21 1971-02-04 Varian Associates Hochfrequenzroehre mit Widerstandsschicht auf der Hochfrequenzleitung
US3922383A (en) * 1974-02-28 1975-11-25 Universal Oil Prod Co Polymeric laminates
US5882726A (en) * 1996-01-02 1999-03-16 Msnw, Inc. Low-temperature densification of carbon fiber preforms by impregnation and pyrolysis of sugars
CN113620696A (zh) * 2021-08-05 2021-11-09 中国科学院福建物质结构研究所 低介电高损耗的氧化硅衰减陶瓷组合物、氧化硅衰减陶瓷及其制备方法和应用
CN116565496A (zh) * 2023-06-27 2023-08-08 济钢防务技术有限公司 一种螺旋线六方衰减器的制备方法

Also Published As

Publication number Publication date
DE1013732B (de) 1957-08-14
NL196805A (en(2012))
NL93132C (en(2012))
FR1131125A (fr) 1957-02-18
GB770083A (en) 1957-03-13

Similar Documents

Publication Publication Date Title
US2911599A (en) Attenuation for traveling-wave tubes
US2880120A (en) Method of manufacturing a microwave attenuator for travelling wave tube
US2771565A (en) Traveling wave tubes
US2606955A (en) Electrical condenser
US2790926A (en) Traveling wave tube
US2720609A (en) Progressive wave tubes
US2413731A (en) Manufacture of electron discharge devices
US2859534A (en) Methods and apparatus for radio frequency freeze-drying
CA1154867A (en) Helix traveling wave tubes with reduced gain variation
US3670197A (en) Delay line structure for traveling wave devices
US4005329A (en) Slow-wave structure attenuation arrangement with reduced frequency sensitivity
US2903657A (en) Wave conductor, particularly for travelling wave tubes
JPS61283185A (ja) 放電管
US2858470A (en) Cathode for electron discharge devices
US3544832A (en) Traveling wave tube with evaporated nickel attenuator coating and method of manufacture thereof
US2994008A (en) Traveling wave electron discharge device
US4292567A (en) In-band resonant loss in TWT's
US3610998A (en) Slow wave circuit and method of fabricating same
US3329855A (en) Helical slow wave structure traveling wave tube having attenuation material coating the inside of the hollow support members
US1954474A (en) Glow cathode
US3015560A (en) Method of fabricating cathode for electron discharge devices
US4835441A (en) Directly heated sorption getter body
US2787723A (en) Electric discharge device structure
US3444615A (en) Process of making a helix support
US3026445A (en) Travelling wave electron discharge tubes