US3675165A - Waveguide window for transmission of electromagnetic waves - Google Patents

Waveguide window for transmission of electromagnetic waves Download PDF

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Publication number
US3675165A
US3675165A US66040A US3675165DA US3675165A US 3675165 A US3675165 A US 3675165A US 66040 A US66040 A US 66040A US 3675165D A US3675165D A US 3675165DA US 3675165 A US3675165 A US 3675165A
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opposite
waveguide
plate
collar
peripheral edge
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Expired - Lifetime
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US66040A
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English (en)
Inventor
Isao Ueda
Takao Kageyama
Isao Inomata
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NEC Corp
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Nippon Electric Co Ltd
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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

Definitions

  • a window for sealing a waveguide gas pressurized to transmit microwave signals comprising: a dielectric plate permeable to the microwave signals, and a mechanical structure hermetically sealing the dielectric plate in the interior of the waveguide and including four openings dimensioned to provide the window with a substantially flat voltage standing wave ratio versus frequency characteristic over a predetermined frequency range, two relatively movable members to permit the dielectric plate to move to compensate for unequal gas pressures on opposite surfaces thereof, and a space to allow movement of the two members to compensate for thermal expansion thereof due to microwave signal loss in the dielectric plate.
  • Sheets-Sheet 2 INVENTORS lsoo Uedo BY Takoo Kugeyomo & lsoo lnomgtp ATTORNEYS WAVEGUIDE WINDOW FOR TRANSMISSION OF ELECTROMAGNETIC WAVES This invention relates to an input or output waveguide window for sealed microwave tubes and to a pressuring window for sealed high-power waveguide means filled with gas such as nitrogen gas.
  • waveguide windows for sealing waveguide systems for high power use are known.
  • waveguide windows there are (l) half-wavelength dielectric resonant windows; (2) cone windows; (3) slanted-disk windows; and (4) circular windows.
  • a ceramic disk of 400 mm in diameter is needed when a waveguide window designed for a 500 MHz band is operated as a circular window.
  • This requires overall window assembly dimensions as large as 410 mm in diameter and 350 mm in thickness.
  • a ceramic block as large as 105 mm by 190.5 mm by 381 mm would be required. Since the axial length of the window becomes as long as 105 mm, the window assembly becomes bulky and heavy.
  • low-loss dielectric materials used for the window such as mica, ceramic, or quartz are expensive, making both manufacture and finishing of these dielectric materials difficult.
  • the dielectric-filled oval-aperture windows for low-power use are advantageous compared with other types of windows such as the circular window, in that both the overall size of the window assembly and the amount of the dielectric material can be reduced. It must be noted however that they have a narrow bandwidth and are weak against thermal expansion as compared with the aforementioned conventional types suited for high-power applications. In other words, it is substantially impossible to manufacture the oval-aperture resonant windows suited for high-power use or large windows of this type for UHF band use.
  • the high-power, broad-band waveguide window of this invention is placed in a rectangular waveguide with the TE mode as the dominant mode.
  • the waveguide window arrangement consists essentially of; (i) a low-loss ceramic plate capable of transmitting high microwave power and of, providing excellent sealing action (i.e., nonporous, etc.) for the waveguide system; (ii) a pair of metallic members bonded to the opposite sides of the ceramic plate. (By the provision of the metallic members on both sides of the plate, aperture dimensions are precisely determined and, at the same time, window failures can be prevented.
  • FIG. 1 shows a cross section of a conventional ceramicbonded oval-aperture resonant window in a rectangular waveguide
  • FIG. 2 is a plan view of the resonant window shown in FIG.
  • FIG. 3 shows a cross section of a resonant window for use in a rectangular waveguide according this invention
  • FIG. 4 shows a plan view of a ceramic plate for use in the embodiment of FIG. 3;
  • FIG. 5 shows a cross section of another embodiment of this invention.
  • FIG. 6 shows a characteristic curve of the embodiment of FIG. 3.
  • a waveguide window of this type is disclosed, for example, in G.L. Ragans paper published on page 221 of "Microwave Transmission Circuit," Vol. 9, M.I.T. Radiation Laboratory Series.
  • the periphery of the surface of the ceramic plate 12 to form a hermetic seal with the apertured metallic plate 13 is metallized so that the ceramic plate 12 can be brazed to the plate 13.
  • the metallic plate 13 is securely bonded to a metallic flange 14 which is securely clamped to the internal wall of the rectangular waveguide by brazing.
  • the ceramic resonant window with a resonant opening 15 in the metallic plate 13 gives a resonance characteristic centered at a desired operating frequency.
  • the aperture 15 has a shape as shown by the broken line.
  • a pair of confronting portions of the metallic flange 14 disposed transverse to the waveguide axis and perpendicular in the direction of the electric field acts as a parallel capacitive susceptance element in the waveguide.
  • the other pair of confronting portions of the metallic flange 14 disposed parallel to the direction of the electric field acts as a parallel inductive susceptance in the waveguide.
  • the resonant opening 15 surrounded by the two pairs of confronting portions may be represented equivalently by a parallel resonant circuit.
  • a ceramic plate in a waveguide window is known to behave so as to increase the above-mentioned parallel capacitance when the waveguide is shown by an equivalent circuit. Therefore, the ceramic resonant window can be matched to a desired resonance frequency by making the width of the window narrower than that of a window with an opening which is not filled with dielectric material. Since the equivalent circuit of such a resonant window containing a dielectric element is a simple resonant circuit without exception, such ceramic windows are narrower in bandwidth than other types of windows such as circular windows. Furthennore, with the increase in the cross sectional area of waveguides adapted to the UI-IF band use, the size of ceramic plates becomes large.
  • the window assembly is sealed in a rectangular waveguide 1 1.
  • the periphery of each of the side surfaces of the ceramic plate 16 is metallized, and a pair of frame members having outer frame 17 and inner frame 18 are brazed to the opposite metallized surfaces of the plate.
  • an inner collar member 19 is brazed substantially in perpendicular relations to each other.
  • One end of an outer collar member 21 outwardly tapered is brazed to the other end of the inner collar 19, and the other end of the outer collar is hermetically fixed to an outer flange member 22 hermetically fixed to the internal wall of the waveguide to form a space 28.
  • That surface of the inner metallic frame 18 which is not brazed to the ceramic plate is slidably mounted on the surface of an inner flange member 23.
  • This window structure may be considered to contain a combination of four resonant apertures that is, a pair of apertures 24 and 25 on opposite sides of the plate 16, an aperture 26 formed in the inner collar 19, and an aperture 27 formed in the inner flange 23.
  • the dielectric coefficient of the ceramic is larger than unity, however, the electrical length for this spacing becomes longer than t (One of the apertures may be greater in area than the other). Therefore, the resonance characteristic of the bandpass filter formed by the two apertures is governed not by the smaller of the two, but by both. Thus, a broadband VSWR characteristic can be obtained.
  • This window structure may be specified as follows; (i) The window is securely held and sealed in place with the aid of the inner collar 19 and the outwardly tapered outer collar 21, contiguous ends of which collars are brazed or welded together. (ii) The free surface of the inner frame 18 is not firmly fixed to the inner flange 23 but only pressed thereto. Thus, the deformation of the window assembly is prevented, that may be caused due to the pressure difference on both sides of the window when the left-hand side of the ceramic plate is evacuated. (iii) Inner collar 19 and outer collar 21 are so arranged as to form space 28 which can accommodate thermal expansion of the outer frame 17 inner frame 18 and ceramic plate 16 when the ceramic plate 16 is heated due to the dielectric loss.
  • a still further advantage of the window structure of FIG. 3 is that the geometry of the plate can be arbitrarily selected. This is because the plate needs to be simply sandwiched between the frame members by brazing and is not subject to limitations of the prior art such as the geometry of the window opening or recessed part of the metallic plate.
  • the size of the ceramic plate used for a WR-ISOO type rectangular waveguide operated at 500 MHz was as small as X I60 X 340 mm and the overall length of the window assembly in the axial direction of the waveguide was of the order of 30 mm.
  • the outer metallic collar 21 may have an outer portion extending to and hermetically fixed to the inner wall of flange member 22, replacing the inner cylindrical collar 19 and the outer collar 21.
  • the ceramic plate 16 used in the window assembly of FIG. 3 is of elongated-octagonal shape.
  • the broken line represents the shape of the aperture 24. It is to be understood that such an octagonal shape facilitates manufacture and finishing of ceramic plates and reduces the manufacturing costs as compared with the conventional ovalshaped ceramic plates, especially when the plate size is made large.
  • each side surface of the ceramic plate 31 is metallized similarly to the previous embodiment.
  • An inner frame 33 and an outer frame 320 formed integrally with an outwardly flared collar 32 are brazed to the opposite metallized surfaces of the ceramic plate.
  • the other end of the collar 32 and one end of outer collar 34 are brazed or welded together.
  • the other end of the outer collar 34 is anchored to the metallic flange 35 to form a hermetic sealing joint.
  • the free surface of the inner frame 33 is anchored to the metallic flange 35 to form a hermetic sealing joint.
  • this window assembly contains four resonant apertures in all that is, apertures 36 and 37 on the opposite sides of the ceramic plate, another aperture 38 in the outwardly flared metallic collar 32, and still another aperture 39 in the metallic flange 35. It is possible with this window assembly to obtain a desired broadband response by suitably varying the dimensions and mutual relationships of these apertures and thereby, controlling their individual rosonance characteristics.
  • FIG. 5 may be considered to be an improved version of the first embodiment in that the outer frame 17 and the inner collar 19 in the structure of FIG. 3 have been replaced with a single-piece outwardly flared collar 32 and that by the adoption of this outwardly flared collar, the flat portion of the response could be further extended.
  • This structure facilitates mounting of the ceramic plate assembly from the left-hand side waveguide section in the window fabrication and, at the same time, helps prevent movement of the ceramic plate assembly, due to the pressure difference on both sides of the window when the left-hand side is evacuated.
  • the VSWR characteristic vs. frequency of a desired bandwidth can be obtained by suitably designing the window assembly so as to contain only one pair of apertures, four apertures, or more/The two metallic frame members brazed on the opposite metallized surfaces may be of any suitable construction other than those described in the embodiments, so far as they contribute to prevention of excessive thermal stresses as mentioned previously and reduce the possibility of consequent deformation or desu'uction of the ceramic plate. Furthermore, there is provided a space in the window assembly of any one of the embodiments for accommodating thermal expansion of the ceramic plate assembly.
  • a window for sealing a waveguide filled with a preselected gas under pressure and transmitting microwave signals without adversely affecting a transmission frequency characteristic of said waveguide comprising:
  • member means having an outer peripheral edge hermetically fixed to an inner surface of said waveguide to project said member means perpendicularly therefrom and having one opposite inner peripheral edge defining a first opening disposed coaxially with a lengthwise axis of said waveguide;
  • a pair of frames so fixedly secured to said plate metallized peripheral opposite surfaces as to include said last-mentioned surfaces therebetween for providing on respective opposite surfaces of said plate second and third openings having a common axis coaxial with said first opening axis; one of said frames movably mounted on an adjacent peripheral surface of said member means proximate to said one opposite edge portion thereof to permit movement of said plate to compensate for occurrences of unequal gas pressures on opposite surfaces thereof; and
  • collar means forming a fourth opening having an axis disposed coaxially with said first, second and third opening axes; said collar means having one entire peripheral edge attached to an adjacent peripheral surface of the other of said frames and an opposite entire peripheral edge hermetically secured to another opposite peripheral edge portion of said member means for providing a fifth opening between said collar means and adjacent surfaces of said one and another edge portions, portions of said member means, said frames and said plate to permit movement of the other of said frames to compensate for thermal expansion of the other frame due to microwave signal power loss in said plate;
  • said first through fourth openings are so dimensioned as to control the resonance characteristics thereof to provide said window with a substantially flat voltage standing wave ratio versus frequency characteristic over a predetermined frequency range.
  • a window for sealing a waveguide filled with a preselected gas under pressure and transmitting microwave signals without adversely affecting a transmission frequency characteristic of said waveguide comprising:
  • member means having an outer peripheral edge hermetically fixed to an inner surface of said waveguide to project said member means perpendicularly therefrom and having one opposite inner peripheral edge portion defining a first opening disposed coaxially with a lengthwise axis of said waveguide;
  • a pair of frames so fixedly secured to said plate metallized peripheral opposite surfaces as to include said last-mentioned surfaces therebetween for providing on respective opposite surfaces of said plate second and third openings having a common axis coaxial with said first opening axis; one of said frames movably mounted on an adjacent peripheral surface of said member means proximate to said one opposite peripheral edge portion thereof to permit movement of said plate to compensate for occurrences of unequal gas pressures on opposite surfaces thereof;
  • a collar fonning a fourth opening having an axis disposed coaxially with said first, second and third opening axes; said collar having an entire peripheral edge attached to an adjacent peripheral surface of the other of said frames;
  • said first through fourth openings are so dimensioned as to control the resonance characteristics thereof to provide said window with a substantially flat voltage standing wave ratio versus frequency characteristic over a predetermined frequency range.
  • a window for sealing a waveguide filled with a preselected gas under pressure and transmitting microwave signals without adversely affecting a transmission characteristic of said waveguide comprising:
  • a member having one peripheral edge hermetically fixed to an inner surface of said waveguide to project said member substantially perpendicularly therefrom and having an opposite peripheral edge defining a first opening disposed coaxially with a lengthwise axis of said waveguide;
  • a pair of frames so fixedly secured to said plate metallized peripheral opposite surfaces as to include said last-mentioned surfaces therebetween for providing on respective opposite surfaces of said plate second and third openings having a common axis coaxial with said first opening axis; one of said frames movably mounted on an adjacent peripheral surface of said member proximate to said opposite edge thereof to permit movement of said plate to compensate for occurrences of unequal gas pressures on opposite surfaces thereof;
  • a flared collar shaping a fourth opening having an axis disposed coaxially with said first, second and third opening axes; said collar having one end formed integrally with an outer peripheral edge of the other frame;
  • said first through fourth openings are so dimentioned as to control the resonance characteristics thereof to provide said window with a substantially flat voltage standing wave ratio versus frequency characteristic over a predetermined frequency range.

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US66040A 1969-09-01 1970-08-21 Waveguide window for transmission of electromagnetic waves Expired - Lifetime US3675165A (en)

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4720693A (en) * 1984-12-28 1988-01-19 Thomson-Csf Ridged rectangular waveguide provided with a sealed window
DE4100922A1 (de) * 1991-01-15 1992-07-16 Krohne Messtechnik Kg Entfernungsmessgeraet, insbesondere zur fuellstandmessung von industrietanks
US5175523A (en) * 1991-03-14 1992-12-29 Varian Associates, Inc. Adjustable coaxial double-disk fluid cooled waveguide window with mean for preventing window bowing
EP0615302A1 (en) * 1993-03-12 1994-09-14 Matra Marconi Space Uk Limited Dielectric resonator filter
US6522226B2 (en) * 2001-06-26 2003-02-18 Raytheon Company Transparent metallic millimeter-wave window
US20030034345A1 (en) * 2001-08-16 2003-02-20 William Conway Waveguide foreign object damage prevention window
US20040263280A1 (en) * 2003-06-30 2004-12-30 Weinstein Michael E. Microstrip-waveguide transition
US20060284709A1 (en) * 2005-03-07 2006-12-21 Sri Hermetics, Inc. And Edward Allen Taylor. Hermetically sealed, weldable connectors
US20130135062A1 (en) * 2011-11-30 2013-05-30 Anritsu Corporation Radio-wave half mirror for millimeter waveband and method of smoothing transmittance
US20130314179A1 (en) * 2012-05-23 2013-11-28 Anritsu Corporation Millimeter waveband filter and method of manufacturing the same
WO2024233506A3 (en) * 2023-05-07 2025-02-06 Elve Inc. Wide-bandwidth radio-frequency (rf) windows and methods

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US2085277A (en) * 1935-02-11 1937-06-29 Corning Glass Works Glass closure for metal containers
US2706275A (en) * 1946-01-21 1955-04-12 Jr Melville Clark Transmission line windows having high voltage breakdown characteristic
GB733655A (en) * 1952-11-26 1955-07-13 Ferranti Ltd Improvements relating to high frequency electrical transmission devices
US2881401A (en) * 1954-01-12 1959-04-07 Gen Electric Waveguide window
US2900568A (en) * 1958-02-17 1959-08-18 Sylvania Electric Prod Microwave switching device
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US2964719A (en) * 1953-11-17 1960-12-13 Robert H Hatch Electronically controlled microwave attenuator
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Publication number Priority date Publication date Assignee Title
US2085277A (en) * 1935-02-11 1937-06-29 Corning Glass Works Glass closure for metal containers
US2706275A (en) * 1946-01-21 1955-04-12 Jr Melville Clark Transmission line windows having high voltage breakdown characteristic
GB733655A (en) * 1952-11-26 1955-07-13 Ferranti Ltd Improvements relating to high frequency electrical transmission devices
US2964719A (en) * 1953-11-17 1960-12-13 Robert H Hatch Electronically controlled microwave attenuator
US2881401A (en) * 1954-01-12 1959-04-07 Gen Electric Waveguide window
US2903614A (en) * 1957-02-11 1959-09-08 Eitel Mccullough Inc Envelope structures for electron tubes
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US3163835A (en) * 1961-09-11 1964-12-29 Ass Elect Ind Voltage-tuneable microwave reactive element utilizing semiconductor material
US3387237A (en) * 1965-12-27 1968-06-04 Varian Associates Microwave window

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Chen RCA, Broadbanding of Resonant Type Microwave Output Windows, RCA Review 6 1954, pp. 204 229 *
Chen; T. S. Output Windows for Tunable Magnetrons, Electronics 5 1954, p. 170 173 *
Vogl, et al., Vacuum Tight Windows with Wide Band Transmission Characteristics, Rev. of Scientific Instruments, Vol. 36 -10 10 65, pp. 1439 1440 *

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4720693A (en) * 1984-12-28 1988-01-19 Thomson-Csf Ridged rectangular waveguide provided with a sealed window
DE4100922A1 (de) * 1991-01-15 1992-07-16 Krohne Messtechnik Kg Entfernungsmessgeraet, insbesondere zur fuellstandmessung von industrietanks
US5175523A (en) * 1991-03-14 1992-12-29 Varian Associates, Inc. Adjustable coaxial double-disk fluid cooled waveguide window with mean for preventing window bowing
EP0615302A1 (en) * 1993-03-12 1994-09-14 Matra Marconi Space Uk Limited Dielectric resonator filter
US6522226B2 (en) * 2001-06-26 2003-02-18 Raytheon Company Transparent metallic millimeter-wave window
US6867401B2 (en) * 2001-08-16 2005-03-15 Communications & Power Industries, Inc. Waveguide foreign object damage prevention window
US20030034345A1 (en) * 2001-08-16 2003-02-20 William Conway Waveguide foreign object damage prevention window
US6967542B2 (en) 2003-06-30 2005-11-22 Lockheed Martin Corporation Microstrip-waveguide transition
US20040263280A1 (en) * 2003-06-30 2004-12-30 Weinstein Michael E. Microstrip-waveguide transition
US20060284709A1 (en) * 2005-03-07 2006-12-21 Sri Hermetics, Inc. And Edward Allen Taylor. Hermetically sealed, weldable connectors
US7365620B2 (en) * 2005-03-07 2008-04-29 Sri Hermetics, Inc. Microwave window with a two part metallic frame having different coefficients of thermal expansion
US20130135062A1 (en) * 2011-11-30 2013-05-30 Anritsu Corporation Radio-wave half mirror for millimeter waveband and method of smoothing transmittance
US9385407B2 (en) * 2011-11-30 2016-07-05 Anritsu Corporation Radio-wave half mirror for millimeter waveband and method of smoothing transmittance
US20130314179A1 (en) * 2012-05-23 2013-11-28 Anritsu Corporation Millimeter waveband filter and method of manufacturing the same
US9160044B2 (en) * 2012-05-23 2015-10-13 Anritsu Corporation Millimeter waveband filter and method of manufacturing the same
WO2024233506A3 (en) * 2023-05-07 2025-02-06 Elve Inc. Wide-bandwidth radio-frequency (rf) windows and methods

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JPS5022865B1 (enrdf_load_stackoverflow) 1975-08-02

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