US2856589A - Light-controlled waveguide attenuator - Google Patents

Light-controlled waveguide attenuator Download PDF

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US2856589A
US2856589A US424400A US42440054A US2856589A US 2856589 A US2856589 A US 2856589A US 424400 A US424400 A US 424400A US 42440054 A US42440054 A US 42440054A US 2856589 A US2856589 A US 2856589A
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waveguide
light
radio frequency
photoconductive
frequency energy
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US424400A
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Kazan Benjamin
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RCA Corp
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RCA Corp
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/24—Frequency- independent attenuators
    • H03H7/27—Frequency- independent attenuators comprising a photo-electric element
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/22—Attenuating devices
    • H01P1/222—Waveguide attenuators
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G1/00—Details of arrangements for controlling amplification
    • H03G1/0005—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal
    • H03G1/0035—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal using continuously variable impedance elements
    • H03G1/0047—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal using continuously variable impedance elements using photo-electric elements

Definitions

  • variable attenuator for use in a waveguide which is capable of varying the attenuation over a broad range at a very rapid rate in response to an electrical control signal.
  • the invention comprises a waveguide having a dielectric or insulating sheet disposed in the waveguide in the direction of the electric vectors of the
  • the dielectric or insulating sheet is covered on one side with photoconductive crystals or a photocond ive powder.
  • the photoconductive material has a very high resistance in darkness, and the resistance decreases as a function of the amount of light which falls on the photoconductive material. With a maximum amount of light dmhotoconductive material, the resistance of the material is so low as to permit currents therein, and to thereby attenuate or reflect radio frequency energy passing thru the Waveguide.
  • Features of the invention include an arrangement whereby a photoconductive material is mounted in a gap structure in the waveguide; a forked waveguide arrangement whereby the division of radio frequency energy in the two forks is readily controllable; and a constant power output waveguide arrangement wherein the attenuation of energy in the waveguide is automatically controlled to provide a constant predetermined output.
  • Figure 1 is a perspective view of a section of the waveguide including an attenuator constructed according to the teachings of this invention
  • Figure 2 is a cross section of a waveguide including a modified form of attenuator
  • Figure 3 is a view of a forked waveguide wherein each of the forks includes a light-controlled waveguide attenuator for controlling the division of energy in the two forks;
  • Figure 4 is an illustration of a waveguide including means to automatically maintain a constant radio frequency output power therefrom.
  • FIG. 1 shows a light-controlled waveguide attenuator.
  • the waveguide 10 is the conventional rectangular metallic waveguide thru which radio frequency electrical energy may be propagated with the electric field vector extending in the vertical direction between the greater sidewalls 11 and 12. Waveguides of other shapes may, of course, be employed provided that consideration is given to the direction of the electric field vector in the waveguide.
  • a sheet 13 of dielectric or insulating material is mounted in the waveguide to extend vertically between the greater sidewalls 11 and 12 and to extend longitudinally thru the waveguide for a limited distance. The insulating or dielectric sheet 13 does not significantly interfere with or effect the propagation of radio frequency energy thru the waveguide.
  • One side of the insulating sheet 13 is coated with a layer 14 of photoconductive crystals or a photoconductive powder.
  • the photocondutcive particles may or may not be arranged so that they contact each other and form a surface extending from the greater sidewall 11 to the greater sidewall 12. Any suitablejgonding technique may be employed to support the photoconductive particles.
  • the bonding material may be such as to provide a selfsupporting structure so that an insulating sheet 13 is not needed.
  • the smaller sidewall 15 of the waveguide 10 is provided witlr an aperture 16.
  • a light bulb 17, or other source of light is disposed outside the waveguide 10 and is oriented with relation to the aperture 16 and the photoconductive layer 14 so that light from the source 17 may be directed thru the aperture 16 to the layer 14.
  • the amount of light directed from the source 17 to the layer 14 may be varied by varying the electric current applied to the light source 17 or by placing a controllable light barrier, for example an opaque shutter, between aperture 16 and source 17.
  • radio frequency energy is directed or propagated along the waveguide 10 in the direction of the arrow 18.
  • the photoconductive layer has a very high resistance so that it is in effect an insulator.
  • the radio frequency energy propagated thru the waveguide is unaffected by the presence of the photoconductive layer 14 therein.
  • the layer 14 becomes conductive as a function of the amount of light falling thereon.
  • the radio frequency energyin the waveguide 10 is to some extent dissipated in the conductive layer 14 .and is therefore prevented from being propagated undiminished thru the waveguide.
  • the resistivity of the layer 14 is a function of the amount of light falling thereon, and that the amount of radio frequency energy propagated thru the waveguide may be controlled by controlling the amount of light from the source 17. Variations in the attenuation in the waveguide may be made as rapidly as the light source 17 may be varied in intensity; subject only to the limitations of the response time of the particular photoconductive material employed.
  • Figure 2 shows a modified form of the invention wherein the greater sidewalls 11' and 12' of the waveguide are provided with conductive protuberances 20, 21 to form a gap structure therebetween.
  • a crystal 22 of photoconductive material is mounted in the gap formed by the protuberances and 21.
  • Light is directed from a source (not shown) thru an aperture 16 to the crystal 22.
  • the gap structure is such as to concentrate or intensity the radio frequency electric field across the crystal .22. Varying amounts of light falling on the crystal 22 produce varying degrees of attenuation of the radio frequency energy.
  • the photoconductive crystal 22 may be a single crystal member, or may e a capsule of crystal particles held in platehlg transparent shell or by a suitable bonding agent.
  • the gap structure and the photoconductive matEi-ial therein may be elongated to extend an appreciable distance along the length of the waveguide.
  • a metallic screen 25 is placed over the aperture 16' to prevent the escape of radio frequency energy from the waveguide thru the aperture 16'. The screen allows light to 'pass thru while confining the radio frequency energy in the waveguide.
  • the aperture 16' may be made sufiiciently small so that radio frequency energy cannot escape even though the metallic screen 25 is omitted.
  • Figure 3 shows a waveguide 26 which is forked to provide two branches 27 and 28.
  • Each of the branches is provided with a layer of phgtggonduntixc. material supported by an insulating sheet after the manner described in connection with Figure l.
  • a light source 29 is associated with one branch 27 and a light source is associated with the other branch 28.
  • Radio frequency energy which passes thru the waveguide 26 may be directed to either the branch 27 or the branch 28 by the synchronous operation of the light sources 29 and 30.
  • light --source 29 is on and lightsource 30 is off, energy is directed thru the branch 28.
  • light source 30 is on and light source 29 is off, energy is directed thru the branch 27.
  • a waveguide 32 is provided with a photoconductive layer 33 which may be illuminated thru an aperture 34 from a light source 35.
  • a radio frequency detector 36 has an input coupled by means of a coupling loop 37 in the interior of the waveguide 32. The out- 0 to a put of the radio frequency detector 36 is applied power amplifier 38. e output of the power amplifier is applied over leadm to the light source 35.
  • radio frequency electrical energy isapplied to'"the waveguide 32 at the left end thereof, from which it is propagated past the photoconductive layer 33,
  • radio frequency energy is attenu: ated until the desired predetermipedi gltggpfsenergsnis,
  • waveguide as used herein is not limited to waveguides of the type commonly used for the transmission of radio frequency energy from one point to another.
  • waveguide is intended to include structures of all kinds-thru which radio frequency energy is propagated with the electric field vector in a predetermined orientatron.
  • a light-controlled waveguide attenuator comprising a waveguide having opposed walls through which radio frequency energy may be propagated, photoconductive material in said waveguide, a support for said photoconductive material positioned between said walls, one of said.
  • walls being provided with an aperture therein, said aperture being in a position to permit light from a source to fall upon said photoconductive material so that said material serves to attenuate radio frequency. energy passing through said waveguide.
  • a light-controlled waveguide attenuator comprising a waveguide through which radio frequency energy may be propagated, said waveguide being rectangular in shape and having greater and lesser side walls, one of said lesser side walls being provided with an aperture therein, photoconductive material positioned in said waveguide and extending from one of said greater side walls to the other of said greater side walls, and a light source external of said waveguide, said aperture being in a position to permit light from said source to fall upon said material so that said material serves to attenuate radio frequency energy passing through said waveguide.
  • a waveguide attenuator comprising, a waveguide having opposed walls, conductive protu'aerances extending from opposite. walls. of said waveguide to form a gap from which two waveguide branches extend, each of said branches having a wall with an aperture therein. a sheet of photoconductive material in. each of said branches extending in the direction of the electric field vectors therein, and means external of said waveguide to direct light through said apertures to said photoconductive sheets in said branches, whereby the radio frequency electric energy passing thru said twobranches may be varied by varying the light directed thereto.
  • a light-controlled waveguide attenuator comprising a waveguide having opposed walls through which radio frequency energy may be propagated, a light source external of said waveguide, one of said walls being constructed to permit light from said lource to be transmitted through a portion thereof, a sheet of photoconductive material positioned in said waveguide to receive light from said source, said photoconductive material being positioned so that its surface is substantially parallel to the I electrical field vector in said waveguide and so that when said material is illuminated by said light source it serves to attenuate radio frequency energy passing through said waveguide.

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Description

FIPBIOF:
Mad
a. KAZAN 2,856,589 LIGHT-CONTROLLED vmvscums xrrsuuuon Filed April 20, 1954 Oct. 14, 1958 I 1' 3 afill m W33 llllllln\ l 1 l I I I l 1 l l I I l 11 I Pan 5e #15 I 4mm.
mmvroa BENJBMm Kazan -radio frequency energy propagated therethru.
United States Patent LIGHT-CONTROLLED WAVEGUIDE A'ITEN UATOR Benjamin Kazan, Princeton, N. 1., asslgnor to Radio Corporation of America, a corporation of Delaware Application April 20, 1954, Serial No. 424,400
8 Claims. (Cl. 333-81) which may be adjustable in position. Of course, a physical device does not lend itself to being moved rapidly and faithfully in response to a controlling force.
ltis an object of this invention to provide a variable attenuator for use in a waveguide which is capable of varying the attenuation over a broad range at a very rapid rate in response to an electrical control signal.
It is another object of this invention to provide a waveguide attenuator including a photoconductive material which changes in conductivity in accordance with the amount of light falling thereon.
It is a further object of this invention to provide a forked waveguide including means to rapidly vary the proportion of the energy directed along the two forks.
It is a further object to provide an improved means for varying the amount of reflected radio frequency energy from a given point in a waveguide.
It is a still further object to provide a novel means "for automatically controlling-"to a predetermined value the amount of radio frequency energy delivered by a waveguide.
In one aspect, the invention comprises a waveguide having a dielectric or insulating sheet disposed in the waveguide in the direction of the electric vectors of the The dielectric or insulating sheet is covered on one side with photoconductive crystals or a photocond ive powder. A lighlmrcmgumlei s o riented with relation to an aperture in a sidewall of the waveguide so that light in varying amounts may be'directed onto the photoconductive material. The photoconductive material has a very high resistance in darkness, and the resistance decreases as a function of the amount of light which falls on the photoconductive material. With a maximum amount of light dmhotoconductive material, the resistance of the material is so low as to permit currents therein, and to thereby attenuate or reflect radio frequency energy passing thru the Waveguide.
Features of the invention include an arrangement whereby a photoconductive material is mounted in a gap structure in the waveguide; a forked waveguide arrangement whereby the division of radio frequency energy in the two forks is readily controllable; and a constant power output waveguide arrangement wherein the attenuation of energy in the waveguide is automatically controlled to provide a constant predetermined output.
These and other objects and aspects of the invention 1 will be apparent to those skilled in the art from the more detailed description taken in conjunction with the appended drawings wherein:
Figure 1 is a perspective view of a section of the waveguide including an attenuator constructed according to the teachings of this invention;
Figure 2 is a cross section of a waveguide including a modified form of attenuator;
Figure 3 is a view of a forked waveguide wherein each of the forks includes a light-controlled waveguide attenuator for controlling the division of energy in the two forks; and
Figure 4 is an illustration of a waveguide including means to automatically maintain a constant radio frequency output power therefrom.
Figure 1 shows a light-controlled waveguide attenuator. The waveguide 10 is the conventional rectangular metallic waveguide thru which radio frequency electrical energy may be propagated with the electric field vector extending in the vertical direction between the greater sidewalls 11 and 12. Waveguides of other shapes may, of course, be employed provided that consideration is given to the direction of the electric field vector in the waveguide. A sheet 13 of dielectric or insulating material is mounted in the waveguide to extend vertically between the greater sidewalls 11 and 12 and to extend longitudinally thru the waveguide for a limited distance. The insulating or dielectric sheet 13 does not significantly interfere with or effect the propagation of radio frequency energy thru the waveguide.
One side of the insulating sheet 13 is coated with a layer 14 of photoconductive crystals or a photoconductive powder. The photocondutcive particles may or may not be arranged so that they contact each other and form a surface extending from the greater sidewall 11 to the greater sidewall 12. Any suitablejgonding technique may be employed to support the photoconductive particles. The bonding material may be such as to provide a selfsupporting structure so that an insulating sheet 13 is not needed.
The smaller sidewall 15 of the waveguide 10 is provided witlr an aperture 16. A light bulb 17, or other source of light, is disposed outside the waveguide 10 and is oriented with relation to the aperture 16 and the photoconductive layer 14 so that light from the source 17 may be directed thru the aperture 16 to the layer 14. The amount of light directed from the source 17 to the layer 14 may be varied by varying the electric current applied to the light source 17 or by placing a controllable light barrier, for example an opaque shutter, between aperture 16 and source 17.
In the operation of the attenuator of Figure 1, radio frequency energy is directed or propagated along the waveguide 10 in the direction of the arrow 18. When the light source 17 is deenergized and no light'falls on the photoconductive layer 14, the photoconductive layer has a very high resistance so that it is in effect an insulator. Under this condition, the radio frequency energy propagated thru the waveguide is unaffected by the presence of the photoconductive layer 14 therein. When light from the source 17 is directed to the photoconductive layer 14, the layer 14 becomes conductive as a function of the amount of light falling thereon. When the photoconductive layer 14 becomes conductive, the radio frequency energyin the waveguide 10 is to some extent dissipated in the conductive layer 14 .and is therefore prevented from being propagated undiminished thru the waveguide. It is apparent that the resistivity of the layer 14 is a function of the amount of light falling thereon, and that the amount of radio frequency energy propagated thru the waveguide may be controlled by controlling the amount of light from the source 17. Variations in the attenuation in the waveguide may be made as rapidly as the light source 17 may be varied in intensity; subject only to the limitations of the response time of the particular photoconductive material employed.
Figure 2 shows a modified form of the invention wherein the greater sidewalls 11' and 12' of the waveguide are provided with conductive protuberances 20, 21 to form a gap structure therebetween. A crystal 22 of photoconductive material is mounted in the gap formed by the protuberances and 21. Light is directed from a source (not shown) thru an aperture 16 to the crystal 22. The gap structure is such as to concentrate or intensity the radio frequency electric field across the crystal .22. Varying amounts of light falling on the crystal 22 produce varying degrees of attenuation of the radio frequency energy.
In Fig. 2, the photoconductive crystal 22 may be a single crystal member, or may e a capsule of crystal particles held in plagehlg transparent shell or by a suitable bonding agent. The gap structure and the photoconductive matEi-ial therein may be elongated to extend an appreciable distance along the length of the waveguide. In Figure 2, a metallic screen 25 is placed over the aperture 16' to prevent the escape of radio frequency energy from the waveguide thru the aperture 16'. The screen allows light to 'pass thru while confining the radio frequency energy in the waveguide. On the other hand, the aperture 16' may be made sufiiciently small so that radio frequency energy cannot escape even though the metallic screen 25 is omitted.
Figure 3 shows a waveguide 26 which is forked to provide two branches 27 and 28. Each of the branches is provided with a layer of phgtggonduntixc. material supported by an insulating sheet after the manner described in connection with Figure l. A light source 29 is associated with one branch 27 and a light source is associated with the other branch 28. Radio frequency energy which passes thru the waveguide 26 may be directed to either the branch 27 or the branch 28 by the synchronous operation of the light sources 29 and 30. When light --source 29 is on and lightsource 30 is off, energy is directed thru the branch 28. Conversely, when light source 30 is on and light source 29 is off, energy is directed thru the branch 27.
Referring to Figure 4, a waveguide 32 is provided with a photoconductive layer 33 which may be illuminated thru an aperture 34 from a light source 35. A radio frequency detector 36 has an input coupled by means of a coupling loop 37 in the interior of the waveguide 32. The out- 0 to a put of the radio frequency detector 36 is applied power amplifier 38. e output of the power amplifier is applied over leadm to the light source 35.
In operation, radio frequency electrical energy isapplied to'"the waveguide 32 at the left end thereof, from which it is propagated past the photoconductive layer 33,
and then past the coupling loop 37 to the output end 40 of the waveguide. A constant value of radio frequency power may be delivered from the output end 40 of the waveguide 32 while a varying amount of power is applied to the input end 41. When a greater than predetermined value of radio frequency energy is coupled from the waveguide by the coupling loop 37, the gligil'gqggltwk En land..app isgislls ifiwflwl -tu as The light frorn the source is is t hus increased to cause the resistance of the photoconductiveda'm to decrease. ;As a result, radio frequency energy is attenu: ated until the desired predetermipedi gltggpfsenergsnis,
delivered at the'ioutputendi til of the waveguide 32-. It 7 is apparent that the system operates as an automatic power control to maintain a constant power output regardless of variations in the input power to the waveguide.
There are various photoconductive materials well known in the art which are suitable for use in the attenu- 4 ators of this invention. is one of the well known phgtials w ich have been found to be particularly suitable.
The term waveguide" as used herein is not limited to waveguides of the type commonly used for the transmission of radio frequency energy from one point to another. The term waveguide" is intended to include structures of all kinds-thru which radio frequency energy is propagated with the electric field vector in a predetermined orientatron.
What is claimed is:
l. A light-controlled waveguide attenuator comprising a waveguide having opposed walls through which radio frequency energy may be propagated, photoconductive material in said waveguide, a support for said photoconductive material positioned between said walls, one of said.
walls being provided with an aperture therein, said aperture being in a position to permit light from a source to fall upon said photoconductive material so that said material serves to attenuate radio frequency. energy passing through said waveguide.
2. A light-controlled waveguide attenuator comprising a waveguide through which radio frequency energy may be propagated, said waveguide being rectangular in shape and having greater and lesser side walls, one of said lesser side walls being provided with an aperture therein, photoconductive material positioned in said waveguide and extending from one of said greater side walls to the other of said greater side walls, and a light source external of said waveguide, said aperture being in a position to permit light from said source to fall upon said material so that said material serves to attenuate radio frequency energy passing through said waveguide.
3. A waveguide attenuator as defined in claim 1, wherein said photoconductive material is in the form of photoconductive powder, and in addition a dielectric sheet in said waveguide supporting said powder.
4. A waveguide attenuator as defined in claim 1, wherein said light source is electrically operated, and in addition, a variable source of electricity connected to energize said light source.
5. A waveguide attenuator as defined in claim 1, wherein said light source is electrically energized, and in addition, a radio frequency detector having an input coupled to the interior of said waveguide, and a power amplifier having an input coupled to the output of said detector, and having an output coupled to said light source, the intensity of said light source being responsive to said output of said detector, whereby the radio frequency energy passing thru said waveguide is automatically controlled.
6. A waveguide attenuator comprising, a waveguide having opposed walls, conductive protu'aerances extending from opposite. walls. of said waveguide to form a gap from which two waveguide branches extend, each of said branches having a wall with an aperture therein. a sheet of photoconductive material in. each of said branches extending in the direction of the electric field vectors therein, and means external of said waveguide to direct light through said apertures to said photoconductive sheets in said branches, whereby the radio frequency electric energy passing thru said twobranches may be varied by varying the light directed thereto.
8. A light-controlled waveguide attenuator comprising a waveguide having opposed walls through which radio frequency energy may be propagated, a light source external of said waveguide, one of said walls being constructed to permit light from said lource to be transmitted through a portion thereof, a sheet of photoconductive material positioned in said waveguide to receive light from said source, said photoconductive material being positioned so that its surface is substantially parallel to the I electrical field vector in said waveguide and so that when said material is illuminated by said light source it serves to attenuate radio frequency energy passing through said waveguide.
6 References Cited in the file of this patent UNITED STATES PATENTS
US424400A 1954-04-20 1954-04-20 Light-controlled waveguide attenuator Expired - Lifetime US2856589A (en)

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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2896086A (en) * 1957-07-01 1959-07-21 Hewlett Packard Co Attenuator network
US2928056A (en) * 1954-05-25 1960-03-08 Rca Corp Means for utilizing solid-state materials and devices for the electronic control of guided electromagnetic wave energy
US2978652A (en) * 1958-09-30 1961-04-04 Rca Corp Microwave modulator
US2982855A (en) * 1959-01-29 1961-05-02 Thompson Ramo Wooldridge Inc Neutron detector
US3222601A (en) * 1962-07-10 1965-12-07 Martin Marietta Corp Antenna beam scanner
DE1259965B (en) * 1963-09-26 1968-02-01 Siemens Ag Device for achieving adjustable damping
US3393381A (en) * 1965-01-21 1968-07-16 Westinghouse Electric Corp Iterative light frequency modulator
US3524016A (en) * 1968-07-31 1970-08-11 Us Army Millimeter wave imaging system
US5099214A (en) * 1989-09-27 1992-03-24 General Electric Company Optically activated waveguide type phase shifter and attenuator
US5969581A (en) * 1998-05-28 1999-10-19 The United States Of America As Represented By The Secretary Of The Navy Opto-electronically controlled RF waveguide
US20030234695A1 (en) * 2002-06-24 2003-12-25 Kazumasa Haruta High-frequency module, transmitter-receiver, and method of adjusting characteristic of the high-frequency module
WO2004038849A1 (en) * 2002-10-25 2004-05-06 Agence Spatiale Europeenne Tuneable phase shifter and/or attenuator
CN105070978A (en) * 2015-08-18 2015-11-18 中国科学技术大学 Non-contact type light-operated high-power waveguide phase shifter

Citations (5)

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Publication number Priority date Publication date Assignee Title
US1811954A (en) * 1928-12-17 1931-06-30 American Telephone & Telegraph Transmission volume control
US2600466A (en) * 1943-05-07 1952-06-17 Bell Telephone Labor Inc Wave guide attenuator
US2640901A (en) * 1950-06-06 1953-06-02 Gen Electric Photoelectric semiconductor device
US2643297A (en) * 1948-12-03 1953-06-23 Fed Telecomm Lab Inc Gas discharge transmission arrangement
US2644926A (en) * 1948-01-09 1953-07-07 Arthur A Varela Electronic switch for highfrequency power

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1811954A (en) * 1928-12-17 1931-06-30 American Telephone & Telegraph Transmission volume control
US2600466A (en) * 1943-05-07 1952-06-17 Bell Telephone Labor Inc Wave guide attenuator
US2644926A (en) * 1948-01-09 1953-07-07 Arthur A Varela Electronic switch for highfrequency power
US2643297A (en) * 1948-12-03 1953-06-23 Fed Telecomm Lab Inc Gas discharge transmission arrangement
US2640901A (en) * 1950-06-06 1953-06-02 Gen Electric Photoelectric semiconductor device

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2928056A (en) * 1954-05-25 1960-03-08 Rca Corp Means for utilizing solid-state materials and devices for the electronic control of guided electromagnetic wave energy
US2896086A (en) * 1957-07-01 1959-07-21 Hewlett Packard Co Attenuator network
US2978652A (en) * 1958-09-30 1961-04-04 Rca Corp Microwave modulator
US2982855A (en) * 1959-01-29 1961-05-02 Thompson Ramo Wooldridge Inc Neutron detector
US3222601A (en) * 1962-07-10 1965-12-07 Martin Marietta Corp Antenna beam scanner
DE1259965B (en) * 1963-09-26 1968-02-01 Siemens Ag Device for achieving adjustable damping
US3393381A (en) * 1965-01-21 1968-07-16 Westinghouse Electric Corp Iterative light frequency modulator
US3524016A (en) * 1968-07-31 1970-08-11 Us Army Millimeter wave imaging system
US5099214A (en) * 1989-09-27 1992-03-24 General Electric Company Optically activated waveguide type phase shifter and attenuator
US5969581A (en) * 1998-05-28 1999-10-19 The United States Of America As Represented By The Secretary Of The Navy Opto-electronically controlled RF waveguide
US20030234695A1 (en) * 2002-06-24 2003-12-25 Kazumasa Haruta High-frequency module, transmitter-receiver, and method of adjusting characteristic of the high-frequency module
EP1376738A1 (en) * 2002-06-24 2004-01-02 Murata Manufacturing Co., Ltd. High-frequency module, transmitter-receiver, and method of adjusting characteristic of the high-frequency module
US6911882B2 (en) 2002-06-24 2005-06-28 Murata Manufacturing Co., Ltd. High-frequency module, transmitter-receiver, and method of adjusting characteristic of the high-frequency module
WO2004038849A1 (en) * 2002-10-25 2004-05-06 Agence Spatiale Europeenne Tuneable phase shifter and/or attenuator
US20050270121A1 (en) * 2002-10-25 2005-12-08 Castiglione Dario C Tuneable phase shfter and/or attenuator
JP2006504128A (en) * 2002-10-25 2006-02-02 アジャンス スパシャル ユーロペエンヌ Tunable phase shifter and / or attenuator
US7283019B2 (en) 2002-10-25 2007-10-16 Agence Spatiale Europeenne Tuneable phase shifter and/or attenuator using photoresponsive-material in a waveguide
EP1923949A1 (en) * 2002-10-25 2008-05-21 Agence Spatiale Europeenne Tuneable phase shifter and/or attenuator
CN100553029C (en) * 2002-10-25 2009-10-21 欧洲空间局 Be used to introduce the equipment of electromagnetic adjustable phase shift and decay
JP2010152390A (en) * 2002-10-25 2010-07-08 Agence Spatiale Europ Tunable phase shifter and/or attenuator
CN105070978A (en) * 2015-08-18 2015-11-18 中国科学技术大学 Non-contact type light-operated high-power waveguide phase shifter

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