US3753171A - Composite microwave window and waveguide transform - Google Patents

Composite microwave window and waveguide transform Download PDF

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Publication number
US3753171A
US3753171A US00131209A US3753171DA US3753171A US 3753171 A US3753171 A US 3753171A US 00131209 A US00131209 A US 00131209A US 3753171D A US3753171D A US 3753171DA US 3753171 A US3753171 A US 3753171A
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United States
Prior art keywords
waveguide
window
height
approximately
wave permeable
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Expired - Lifetime
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US00131209A
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English (en)
Inventor
R Butwell
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Varian Medical Systems Inc
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Varian Associates Inc
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/08—Dielectric windows
    • 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
    • H01J23/36—Coupling devices having distributed capacitance and inductance, structurally associated with the tube, for introducing or removing wave energy

Definitions

  • COMPOSITE MICROWAVE WINDOW AND WAVEGUIDE TRANSFORM 1 DESCRIPTION OF THE PRIORART dow has the advantagethat it is capable of passing relatively high microwave power levels, as of 4MW peak at Sband, and relatively high average powers, as of 8 KW average, over a relatively wide band of frequencies, asof to 30% with a VSWR less than 1.1.
  • This prior art window is typically usedas the output window of a high powerpulsedrriicrowave tube, such as a klystron, traveling wave tube or magnetron.
  • thewaveguide feeding outwardly of the microwave tube generally has a reduced height compared to normal waveguide to accommodate magnetic beam focusing structure and the like typically surroundingthe tube.
  • the output waveguide normally has a reduced height in order to have a lower characteristic impedance for providing an improved waveguide match to the outputload impedance of the tube.
  • the principal object .of the present invention is the provision of an improvedcomposite microwave window and waveguide transformer.
  • One feature of the present invention is the provision of a composite microwave window and waveguide transformer wherein afirst section of waveguide, which band impedance match to form a composite microwave window and transformer.
  • the first waveguide is of circular cross section and the second and third connecting waveguides are of rectangular cross section andthe abruptwaveguide transitions include walls at opposite ends of the first waveguide section with rectangular apertures for providing wave en LII ergy communication between the second and third and first waveguide sections.
  • thelow impedance rectangular'connecting waveguide has a heightof approximately /5 of itswidth and the third waveguide is rectangular having a height which is approximately V: of its width.
  • Thewindow structure 1 includes a first section of hollow cylindrical waveguide 2 approximately an integral number of IIQWZVCIBHEIIIS long atthe center frequencyof the passband of the window 1.
  • the cylindrical section of waveguide 2 is closed at opposite ends by centrally aperture-d end walls 3 and 4.
  • Rectangular waveguides Sand 6 of substantially lower height waveguidethan the center cylindrical section 2 are connected to the center section; 2 via therectangular apertures 7 and 8 in opposite end walls 3and 4.
  • the apertures 7 and 8 are of the same dimensions as the inside dimensions of the rectangular waveguidesSand 6, respectively.
  • the centrally apertured end walls 3and4 provide abrupt waveguide transitions from the waveguides 5 and 6 to the central waveguide section 2.
  • a disc shaped wave permeable window member 9, as of alumina ceramic, is heremetically sealed, as by brazing, transversly across the central waveguide section 2 at a point substantially midway pf its length.
  • Such a prior art window provides a relatively broad band structure typically having apassband of approximately 20% and being capable of passing relatively high power, as of MW peak power and KW average power.
  • the prior art windowof FIG. 1 When the prior art windowof FIG. 1 is employed as partially cut away, of a the output window in the typical microwave tube it is desired to utilize a waveguide transformer for connect ing the normal height waveguide 5 to the outputwaveguide of the microwave tube.
  • the output waveguide of the microwave tube is shown at 11 inFlG. 2*and is normally of reduced height having a height h, as of 15 of its width, where the heigh h and the width w are shown inFlG. 1.
  • the transformer is indicated at 12 in FIG. 2 and it may comprise a uniform taper in height of the guide or, as an alternative, one or more steps in the height of the guide, as shown in FIG. 2, for effecting an impedance match between the low height guide 11 and the nonnalheight guide 5.
  • Such impedance transformers 12 utilize additional space and are relatively costly to manufacture.
  • FIG. 3 there is shown a composite microwave window and waveguide transformer 15 incorporating features of the present invention.
  • the structure of the composite microwave window and waveguide transformer 15 is substantially the same as that previously described with regard to FIG. 1 and 2 with the exception that the input waveguide 5, which is connected to the central waveguide section 2, is of reduced height. More particularly the input waveguide is of rectangular cross section having a height h approximately #5 of its width w.
  • the coupling hole 7 in the end wall 4 is of rectangular cross section having a cross section of the same dimensions as the inside cross section of the low impedance input waveguide 5.
  • the microwave window member 9 is sealed across the center cylindrical waveguide section 2 at a point which is displaced from the midpoint toward the waveguide of reduced height, namely, waveguide 5.
  • the window member 9 is displaced by an amount to produce a broadband match such that the composite microwave window with the displaced window member 9 forms a composite microwave window and impedance transformer.
  • the center of the microwave window 9 is displaced from the midpoint of the length of cylindrical waveguide 2 by approximately 17% of the length of the waveguide 2.
  • Waveguide 2 has a length l which is approximately 85% of k of a free space wavelength.
  • the window 9 is dimensioned such that the distance d between the regions just inside the connecting waveguides 5 and 6, at the abrupt transitions 7 and 8, is approximately A of an electrical wavelength when taking into effect the loading produced by the window 9 and the fringing field regions at the abrupt transitions, such fringing field regions extending slightly into the adjacent waveguide sections 5 and 6.
  • d could be n/2 electricial wavelengths where n is any odd integer.
  • input waveguide 5 had a width of 2.84 inches and a height which was of the normal height, namely 0.892 inch.
  • the output guide 6 had a width of 2.84 inches and a height of 1.34 inches.
  • the cylindrical waveguide section 2 had a diameter of 9.03 centimeters and a length l of 3.85 centimeters.
  • the window member 9 was made of alumina ceramic having a thickness of 0.36 centimeters.
  • the composite microwave window and waveguide transformer of the aforecited dimensions had a passband characteristic as shown in FIG. 4, wherein the passband was approximately 13% or 400 MHz between VSWR points of 1.1 centered at a frequency of approximately 2.8 GHz.
  • the composite microwave window and transformer 15 passed 4 MW peak and greater than 8 KW average power.
  • the output waveguide 6 and that portion of the central waveguide section 2 in gas communication therewith was pressurized with SP at a pressure of approximately 25 psi gauge.
  • the input waveguide 5 was connected via flange 17 to the output waveguide of the microwave tube not shown, and the output waveguide 6 was connected to conventional standard size S- band waveguide via waveguide flange 18.
  • a first tubular waveguide member having a first height
  • second and third tubular waveguide members having waveguide heights substantially less than the height of said first guide, centrally apertured end walls of said first waveguide member forming abrupt waveguide transitions for connecting said second and third waveguide members to said first waveguide member substantially at the ends of the said first waveguide member
  • a gas tight wave permeable window member disposed transversely of and within said first waveguide member, the thickness of said wave permeable window member being substantially less than A of an electrical wavelength at the center frequency of the passband of the wave permeable window assembly, and the length of said first waveguide member plus the fringing field regions extending into the adjacent second and third waveguides at said abrupt transitions, and with said wave permeable window in place, being approximately n/2 electrical wavelengths long at the center frequency of the certain passband of said window assembly, where n can have any odd integer value
  • said second wave having a first height
  • second and third tubular waveguide members having waveguide heights substantially less than the height of said first

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US00131209A 1971-04-05 1971-04-05 Composite microwave window and waveguide transform Expired - Lifetime US3753171A (en)

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US13120971A 1971-04-05 1971-04-05

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US (1) US3753171A (2)
CA (1) CA956373A (2)
DE (1) DE2214522A1 (2)
FR (1) FR2132180B1 (2)
GB (1) GB1365644A (2)
NL (1) NL7204487A (2)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3993969A (en) * 1974-11-15 1976-11-23 Siemens Aktiengesellschaft Vacuum-tight window arrangement for rectangular waveguides
US4668894A (en) * 1981-04-27 1987-05-26 The United States Of America As Represented By The Secretary Of The Navy Waveguide coupler using three or more wave modes
FR2604307A1 (fr) * 1986-09-19 1988-03-25 Spinner Georg Piece de transformation pour relier des guides d'ondes de sections differentes
JP3341101B2 (ja) 1995-07-28 2002-11-05 日本電気エンジニアリング株式会社 アンテナ気密構造
RU2451362C1 (ru) * 2011-02-02 2012-05-20 Федеральное государственное унитарное предприятие "Научно-производственное предприятие "Исток" (ФГУП "НПП "Исток") Баночное окно ввода и/или вывода свч-энергии
RU2705563C1 (ru) * 2019-02-26 2019-11-08 Акционерное общество "Научно-производственное предприятие "Исток" имени А.И. Шокина" (АО "НПП "Исток" им. Шокина") Баночное окно ввода-вывода энергии свч

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2558306B1 (fr) * 1984-01-17 1988-01-22 Thomson Csf Fenetre circulaire pour guide d'onde hyperfrequence
GB8925000D0 (en) * 1989-11-06 1990-05-30 Eev Ltd Magnetrons
US5461283A (en) * 1993-07-29 1995-10-24 Litton Systems, Inc. Magnetron output transition apparatus having a circular to rectangular waveguide adapter

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2698421A (en) * 1952-05-23 1954-12-28 Raytheon Mfg Co Wave guide seal and filter structure
US2958834A (en) * 1956-06-13 1960-11-01 Varian Associates Sealed wave guide window
US3221278A (en) * 1962-07-13 1965-11-30 Hughes Aircraft Co Microwave tube transformer-window
US3221206A (en) * 1964-02-21 1965-11-30 Varian Associates Output window and coupler for high frequency electron discharge device
US3278865A (en) * 1963-05-31 1966-10-11 Kane Engineering Lab Device using multipactor discharge
US3309558A (en) * 1963-10-07 1967-03-14 Varian Associates Electromagnetic wave transmission systems including a dielectric window for transmitting high-frequency highpower electromagnetic energy to a load from a source of suchenergy such as a resonant cavity of a klystron

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2698421A (en) * 1952-05-23 1954-12-28 Raytheon Mfg Co Wave guide seal and filter structure
US2958834A (en) * 1956-06-13 1960-11-01 Varian Associates Sealed wave guide window
US3221278A (en) * 1962-07-13 1965-11-30 Hughes Aircraft Co Microwave tube transformer-window
US3278865A (en) * 1963-05-31 1966-10-11 Kane Engineering Lab Device using multipactor discharge
US3309558A (en) * 1963-10-07 1967-03-14 Varian Associates Electromagnetic wave transmission systems including a dielectric window for transmitting high-frequency highpower electromagnetic energy to a load from a source of suchenergy such as a resonant cavity of a klystron
US3221206A (en) * 1964-02-21 1965-11-30 Varian Associates Output window and coupler for high frequency electron discharge device

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
Bethe, H. A., Theory of Diffraction by Small Holes, Physical Review vol. 66, 1944, pp. 177 178 *
Collins, G. B., Microwave Magnetrons, McGraw Hill, 1948, pp. 488 *
Hudson, A. C., Circular Waveguide Chart, Electronics 10 1954, pp. 194 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3993969A (en) * 1974-11-15 1976-11-23 Siemens Aktiengesellschaft Vacuum-tight window arrangement for rectangular waveguides
US4668894A (en) * 1981-04-27 1987-05-26 The United States Of America As Represented By The Secretary Of The Navy Waveguide coupler using three or more wave modes
FR2604307A1 (fr) * 1986-09-19 1988-03-25 Spinner Georg Piece de transformation pour relier des guides d'ondes de sections differentes
JP3341101B2 (ja) 1995-07-28 2002-11-05 日本電気エンジニアリング株式会社 アンテナ気密構造
RU2451362C1 (ru) * 2011-02-02 2012-05-20 Федеральное государственное унитарное предприятие "Научно-производственное предприятие "Исток" (ФГУП "НПП "Исток") Баночное окно ввода и/или вывода свч-энергии
RU2705563C1 (ru) * 2019-02-26 2019-11-08 Акционерное общество "Научно-производственное предприятие "Исток" имени А.И. Шокина" (АО "НПП "Исток" им. Шокина") Баночное окно ввода-вывода энергии свч

Also Published As

Publication number Publication date
CA956373A (en) 1974-10-15
FR2132180B1 (2) 1976-10-29
DE2214522A1 (de) 1972-10-12
NL7204487A (2) 1972-10-09
GB1365644A (en) 1974-09-04
FR2132180A1 (2) 1972-11-17

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