GB2225122A - An apparatus for producing a phase shift in a beam of electromagnetic radiation - Google Patents
An apparatus for producing a phase shift in a beam of electromagnetic radiation Download PDFInfo
- Publication number
- GB2225122A GB2225122A GB8826251A GB8826251A GB2225122A GB 2225122 A GB2225122 A GB 2225122A GB 8826251 A GB8826251 A GB 8826251A GB 8826251 A GB8826251 A GB 8826251A GB 2225122 A GB2225122 A GB 2225122A
- Authority
- GB
- United Kingdom
- Prior art keywords
- layer
- liquid crystal
- radiation
- phase shift
- potential difference
- 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.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/29—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the position or the direction of light beams, i.e. deflection
- G02F1/292—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the position or the direction of light beams, i.e. deflection by controlled diffraction or phased-array beam steering
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/137—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
- G02F1/139—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
- H01Q3/44—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the electric or magnetic characteristics of reflecting, refracting, or diffracting devices associated with the radiating element
- H01Q3/46—Active lenses or reflecting arrays
Landscapes
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Liquid Crystal (AREA)
Abstract
An apparatus is provided for producing a phase shift in a beam of electromagnetic radiation. The apparatus includes a first layer (2) of a dielectric material, and a second layer (4) of an electrically conductive and thus highly reflective material parallel to the first layer and separated from the first layer by a gap. A layer (6) of a liquid crystal material is positioned between the first layer (2) and the second layer (4). When a potential difference is applied across the liquid crystal layer (6) the refractive index of the liquid crystal material is changed. The change in the refractive index of the liquid crystal material effects a change in the phase shift produced in the beam of radiation emitted from the apparatus. <IMAGE>
Description
AN APPARATUS FOR PRODUCING A PHASE SHIFT IN A BEAM
OF ELECTROMAGNETIC RADIATION
This invention relates to an apparatus for producing a phase shift in a beam of electromagnetic radiation. In particular, though not exclusively, this invention relates to an apparatus for steering or scanning a beam of electromagnetic radiation.
It is known to use mechanically scanned antennas at microwave and millimetre-wave frequencies as a means of steering radar or communication transmit and receive beams. These suffer from limited scan rates due to mechanical inertia and can be expensive to manufacture. Cost can be a particularly severe constraint in the case of applications involving large quantities in production.
Phased array techniques are well known in radar applications. However, although they offer fast beam steering, their use is limited because of the high costs involved in array manufacture. This is due to the complex microwave circuits, such as digitally controlled phase shifters and amplifiers, included in each element of the array, especially when the array itself may consist of up to several thousand such modules.
Other beam steering techniques which have been proposed use 'distributed' or 'spatial' structures rather than separate electronically controlled microwave modules. These include diode grid arrays and piezo-electric tuned interferometers.
None of these techniques have been particularly successful, often due to practical considerations.
FR 2254057 (Thomson-CSF) and US 4639091 (Auignard et al assigned to Thomson-CSF) disclose a device for deflecting a beam of coherent polarized radiation into a specific set of predetermined directions, using the principle of a diffraction grating. The grating consists of a liquid-crystal substance.
The application of an electric field can achieve a local variation in the phase difference introduced by the substance in an electric field and hence a variation in the spacing of the diffraction grating. This allows deflection of an incident beam of coherent polarized radiation in any single direction in a series of discrete, predetermined directions.
However, a problem with such a device is that the phase difference that can be produced using known liquid crystal substances means that in order to produce a large phase difference, it is necessary to use a relatively thick liquid crystal cell with a consequentially poor response to an applied field.
It is an object of the present invention to provide an apparatus for producing a phase shift in an electromagnetic beam of radiation which at least alleviates the problems outlined hereinbefore.
According to the present invention there is provided an apparatus for producing a phase shift in a beam of electromagnetic radiation, the apparatus comprising a first layer of a dielectric material, a second layer of an electrically conductive and thus highly reflective material parallel to said first layer and separated from said first layer by a gap, a layer of a liquid crystal material between said first and said second layer, and means for applying a potential difference across the liquid crystal layer whereby the refractive index of the liquid crystal material can be changed, wherein a change in the refractive index of the liquid crystal material effects a change in the phase shift produced in the beam of radiation emitted from the apparatus.
Electromagnetic radiation incident on the first layer is multiply reflected as a standing wave between the first and second layers. Accordingly if a dielectric material having a sufficiently high dielectric constant is used for the first layer, it is possible with the apparatus of the present invention to produce a phase shift over a range approaching 3600.
Embodiments of the invention will now be described, by way of example only, and with reference to the accompanying schematic drawings in which:
Figure 1 shows part of an apparatus provided in accordance with the present invention for producing a phase shift in a beam of electromagnetic radiation;
Figures 2a and 2b illustrate the theory of operation of the present invention;
Figure 3 shows the apparatus of Figure 1 modified for deflecting a beam of electromagnetic radiation in a required direction;
Figure 4 shows an exploded view of a first embodiment of an apparatus for two dimensional steering or scanning of a beam of electromagnetic radiation;
Figure 5 shows a possible arrangement of electrical connections to the electrodes in the apparatus of Figure 4;;
Figures 6 and 7 show a second embodiment of an apparatus for two dimensional steering or scanning of a beam of electromagnetic radiation.
Figure 1 shows schematically part of an apparatus provided in accordance with the present invention. The apparatus is defined by a first layer 2 of a dielectric material and a second layer 4 of an electrically conductive and thus highly reflective material, such as a metal, separated from the first layer 2 by a gap 5. Between the dielectric layer 2 and the reflective layer 4 is provided a thin layer 6 of a liquid crystal material supported by supporting layers (not shown) of a material having a low dielectric constant, such as quartz or low loss glass.
An electric field can be applied across the liquid crystal layer 6 using a first electrode 8 and a second electrode 9 of a conducting material. The first and second electrodes 8, 9 are sufficiently thin, e.g. 1.0 FLm, and of a low enough conductivity to appear transparent to the electromagnetic radiation of interest. For microwave radiation, a suitable electrode material is silicon or indium tin oxide.
Alternatively, the electrodes can be formed of parallel grid lines which appear transparent to a single plane of polarization of electromagnetic radiation when the electric vector of the electromagnetic wave is perpendicular to the grid lines.
Application of an electric field across the liquid crystal layer 6 results in an effective change in its refractive index, for a particular polarization of radiation, which effects a change in the phase shift produced in radiation incident on the apparatus.
The theory of operation of the apparatus is described below with reference to Figures 2a and 2b. Figure 2a shows schematically a basic structure comprising a first layer 10 of a dielectric material, of dielectric constant E r and a second layer 12 of a reflective and electrically conductive material, the first and second layers 10, 12 being parallel to each other and separated from each other by a distance x. Radiation of frequency f incident on the first surface 14 of the dielectric layer 10 and propagating in a direction normal to the surface 14 has a wavelength Sd in the dielectric layer 10 and a
d wavelength AO in the gap between the dielectric layer 10 and the reflective layer 12.
Standing waves are established between the dielectric layer 10 and the reflective layer 12 when radiation is incident on the surface 14, the effect being that the radiation is transmitted from the structure with a phase of reflection /. This phase of reflection is the phase shift produced when the radiation is emitted from the structure and apparently reflected from the dielectric layer 10. Figure 2b is a graph showing variation of the phase of reflection / with the separation x of the dielectric layer 10 and reflective layer 12 for different values of fr' thickness of the dielectric layer 10 being approximately rod/4. The graph shows that for x approximately equal to at/2, the phase of reflection varies greatly with x.Accordingly, the phase shift produced by the structure is very sensitive to the position of the reflective layer 12 relative to the dielectric layer 10. This sensitivity increases with
Accordingly, referring to Figure 1, when an electric field is applied across the liquid crystal layer 6, this changes the refractive index of the layer - the refractive index varying with the applied potential difference. This changes the phase constant of propagation of the radiation through the liquid crystal layer 6 and so changes the effective separation of the dielectric layer 2 and the reflective layer 4. Thus the phase shift produced by the apparatus when radiation is incident on the front surface 16 of the dielectric layer 2 can be changed.
Advantageously, the actual separation of the dielectric layer 2 and the reflective layer 4 is approximately jo/2 (where at = wavelength of the incident radiation in the gap 5) and so the apparatus is most sensitive to the effect of changing the refractive index of the liquid crystal layer 6.
It has been found that if the dielectric constant r of the dielectric layer 2 is sufficiently high in relation to the phase shift which can be produced by the liquid crystal layer alone then it is possible to control the phase shift produced by the apparatus through approximately 3600 e.g. if the phase shift which can be produced by the liquid crystal layer alone is 100, then for radiation of frequency 100 CHz, a suitable dielectric material for the dielectric layer 2 could have a dielectric constant of 100.
The return loss of reflection (i.e. the power loss from incident radiation because it has passed through and been reflected from the apparatus) is dependent on the dielectric loss within the liquid crystal layer 6 and also on the position of this layer 6 between the dielectric layer 2 and the reflective layer 4, allowing some degree of optimisation.In one example, for which computer simulated results have been obtained, the dimensions and variables were as follows:
Frequency of incident radiation = 94GBz r of dielectric layer 2 = 150
Liquid crystal material is an eutectric mixture of cynano biphenyls, such as alkyl - cyanobiphenyl (commercial supplier BODE, material type :E7)
Thickness of liquid crystal
layer 6 = 200
Separation of liquid crystal = in the range of from
layer 6 from dielectric layer 2 1 mm to 1.5 mm
Material of reflective layer 4 is copper
Separation of reflective layer
4 from liquid crystal layer 6. = zero
Maximum phase shift produced by
liquid crystal layer 6 alone - 3.30 Maximum phase shift produced
by apparatus = 3150
Fabricated devices produced have not been able to achieve such good results, due to inadequacies in the fabricated structure and electrode format and also due to limitations in the measurement techniques used.
In a modification of the apparatus of Figure 1, a plurality of liquid crystal layers, each with its respective first and second electrode are provided in the gap between the dielectric layer and the reflective layer. As with the apparatus of Figure 1, application of a potential difference across each of the liquid crystal layers changes the effective separation of the dielectric layer and the reflective layer. Such a modification could also be used to implement incremental phase shifting, e.g.
three layers of a bistable liquid crystal material could be used to produce incremental phase shifting in 8 equal steps.
Spacings between the individual liquid crystal layers could be made thicker than the layers themselves to provide greater variation in the effective separation of the dielectric layer and the reflective layer. This could reduce the requirements on the high dielectric constant dielectric layer or allow the use of thinner liquid crystal layers with a consequent increase in switching response.
In another modification to the apparatus of Figure 1, a common conducting and reflective layer is used as both the reflective layer 4 and the first electrode layer 8. A suitable material for such a layer is a metal such as copper or aluminium.
In a further modification, an array of phase controlled reflecting elements to deflect a beam of electromagnetic radiation in a required direction can be fabricated by replacing one of the electrodes by a periodic structure or 'mosaic' of separable electrodes, as shown in cross-section in Figure 3.
The apparatus of Figure 3, a reflective linear phased array, is similar in structure to the apparatus of Figure 1 and so like parts are designated by like reference numerals. The first electrode layer 8 is formed as a set of strip electrodes 8j, 8k, 81, to define respective elements 6j, 6k, 61 of the liquid crystal layer 6. Application of a different potential to each strip electrode 8j, 8k, 81 and hence a different potential difference across each liquid crystal element 6j, 6k, 61 produces a change in the refractive index of each liquid crystal element local to that element.Accordingly, a different phase shift is produced in a beam of radiation incident on each liquid crystal element 6j, 6k, 61 and interference of the radiation having different phases produces a beam of radiation apparently reflected from the front surface 16 of the apparatus which is directed in a required direction.
Variation of the potential difference applied to each liquid crystal element with time allows a beam of radiation incident on the front surface 16 of the apparatus to be steered, i.e. reflected from the apparatus at a given angle which can be varied, or alternatively allows scanning of radiation incident on the front surface 16 over a wide angle. The maximum rate of steering or scanning is dependent on the response time of the liquid crystal material. This response time is itself dependent on the method of controlling the applied voltages, the nature of the electrode material properties and the electrode dimensions.
Anticipated switching times are less than tens of milliseconds.
The apparatus of Figure 3 allows steering or scanning of radiation in one dimension, i.e. in one plane. Two dimensional single beam steering or multiple beam formation can be implemented with the apparatus of Figure 4. This shows an exploded view of a planar phased array scanner 20. A liquid crystal layer 22 comprises a matrix of elements defined by a matrix of electrodes 24 on one surface of the liquid crystal layer 22. An electrode layer 26 common to all the liquid crystal elements is provided on the other surface of the liquid crystal layer 22. A high permittivity dielectric layer 28 is spaced from the electrode layer 26 by a low permittivity single or composite dielectric layer 29.
The matrix of electrodes 24 is formed as a tesselated structure of a material, such as a metal, which is effective as both an electrode layer and as the reflective and conducting layer defining one end of the apparatus. The matrix of electrodes is addressed in known manner from circuits outside the electrode structure by conducting lines positioned in the gaps between the electrodes. The applied potential difference across a liquid crystal element determines its refractive index and hence the phase shift which can be produced in radiation incident thereon.
Alternatively as shown in Figure 5, each electrode 24 can be addressed by a planar integrated circuit element 30 (illustrated, for simplicity, as a single fet) positioned at the cross-over of X- and Y- narrow conducting wires 32, 34. The circuit element 30 provides the necessary threshold and logic circuitry to produce the required potential at the electrode 24 in response to the potentials applied at the X- and Y conducting wires 32, 34 and also includes circuitry to give a degree of bistability to the switching characteristic of the liquid crystal elements. In operation, a beam is steered or scanned by applying appropriate potentials line-by-line to the
X- and Y- conducting wires 32, 34. The applied potential difference across a liquid crystal element determines its refractive index and hence the phase shift which can be produced in radiation incident thereon.Because of the degree of bistability provided by the circuit element 30, each liquid crystal element remains in a particular state until it is again addressed.
For operation with microwave radiation of frequency about 100 GHz (wavelength in free space about 3mm), a typical apparatus has a liquid crystal layer approximately 200 cm thick and comprises a matrix of up to thousands of elements of approximately 1.5 mm square dimension. For operation with radiation in the far infra-red of frequency about 1014Hz (wavelength in free space about 10 mem), suitable dimensions are a liquid crystal layer of thickness 2 to 5 em and an element pitch of about 5tax. A liquid crystal material with a positive dielectric anisotropy, such as MBBA: EBBA: EBAB in the ratio 2:2:1, is preferred for a fast response.Optionally a magnetic field can be applied parallel to the electrode layers to further speed up the response time of the liquid crystal material.
Two dimensional single beam steering can also be implemented with an apparatus shown schematically in Figure 6.
This shows a first reflective linear phased array 40 and a second reflective linear phased array 42. The first array 40 deflects an incident beam in a first plane, so that it is incident on the second array 42 which deflects the beam in a second plane orthogonal to the first plane. Such an apparatus is particularly useful for steering or scanning radiation of infra-red frequencies as it obviates the need for the production of electrode structures of dimensions of the order of micrometres which, as outlined hereinbefore, would be necessary to provide two dimensional steering or scanning of infra-red radiation.
The structure of a reflective linear phased array 44 for use with radiation of infra-red radiation is shown in Figure 7.
A liquid crystal layer 46 comprises a plurality of strips defined by a plurality of electrode strips 48 on one surface of the liquid crfystal layer 46. These strips 48 are effective as both an electrode layer and as the reflective and conducting layer defining one end of the apparatus. An electrode layer 50 common to all the liquid crystal strips is provided on the other surface of the liquid crystal layer 46 as a silicon film. Next to the electrode layer 50 is provided an infra-red transmissive substrate 52, such as barium fluoride. A further electrode layer 54 is provided on the other surface of the substrate 52.
In order to produce a phase shift to steer or scan a beam of radiation, a potential difference is applied across the liquid crystal layer 46 via the electrode strips 48 and the electrode layer 50. The electrode layers 50, 54 on either side of the substrate 52 are held at a common potential.
Modifications to the embodiments described will be apparent to those skilled in the art.
Claims (12)
1. An apparatus for producing a phase shift in a beam of electromagnetic radiation, the apparatus comprising a first layer of a dielectric material, a second layer of an electrically conductive and thus highly reflective material parallel to said first layer and separated from said first layer by a gap, a layer of a liquid crystal material between said first and said second layer, and means for applying a potential difference across the liquid crystal layer whereby the refractive index of the liquid crystal material can be changed, wherein a change in the refractive index of the liquid crystal material effects a change in the phase shift produced in the beam of radiation emitted from the apparatus.
2. An apparatus according to Claim 1, the beam of electromagnetic radiation comprising radiation having a predetermined wavelength > in said gap wherein said first and
0 said second layers are separated by a distance approximately equal to
3. An apparatus according to Claims 1 or 2, the radiation having a predetermined wavelengthAd in said first layer wherein said first layer has a thickness approximately equal to
4. An apparatus according to any one of Claims 1 to 3 wherein said second layer is formed of a metal.
5. An apparatus according to any one of Claims 1 to 4 further comprising one or more other layers of liquid crystal material between said first and said second layer, and respective means for applying a potential difference across each one or more other layers.
6. An apparatus according to any one of Claims 1 to 5 wherein said means for applying a potential difference comprise a first electrode on one face of the liquid crystal layer and a second electrode on the other face of the liquid crystal layer.
7. An apparatus according to Claim 6 wherein said first electrode comprises a first set of electrodes, each member of said first set of electrodes defining a respective element of the liquid crystal layer, the apparatus further comprising means for applying a potential to each member of said first set of electrodes whereby a different potential difference can be applied to a respective element to produce a different phase shift in a beam of radiation incident on said a respective element, the arrangement being such that a beam or a number of beams of electromagnetic radiation emitted from the apparatus is directed in a required direction.
8. An apparatus according to Claim 7 further comprising means for varying the potential difference applied to each element, the arrangement being such that the direction in which the beam of radiation emitted from the apparatus is directed can be varied.
9. An apparatus according to Claim 7 further comprising means for varying the potential difference applied to each element, the arrangement being such that beams of radiation incident on the apparatus over an area can be scanned.
10. An apparatus according to any one of Claims 7 to 9 wherein said first set of electrodes comprises a matrix of elements.
11. The combination of a first apparatus according to any one of Claims 7 to 10 and a second apparatus according to any one of
Claims 7 to 10, the arrangement being such that a beam of radiation emitted from said first apparatus is emitted in a first plane and a beam of radiation emitted from said second apparatus is emitted in a second plane at an angle to said first plane.
12. An apparatus substantially as hereinbefore described with reference to and as illustrated in any one of the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8826251A GB2225122B (en) | 1988-11-09 | 1988-11-09 | An apparatus for producing a phase shift in a beam of electromagnetic radiation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8826251A GB2225122B (en) | 1988-11-09 | 1988-11-09 | An apparatus for producing a phase shift in a beam of electromagnetic radiation |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8826251D0 GB8826251D0 (en) | 1989-05-17 |
| GB2225122A true GB2225122A (en) | 1990-05-23 |
| GB2225122B GB2225122B (en) | 1992-12-23 |
Family
ID=10646585
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8826251A Expired - Lifetime GB2225122B (en) | 1988-11-09 | 1988-11-09 | An apparatus for producing a phase shift in a beam of electromagnetic radiation |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2225122B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0519772A1 (en) * | 1991-06-18 | 1992-12-23 | Thomson-Csf | Microwave antenna with optoelectronical controlled scanning |
| EP0856767A2 (en) * | 1997-01-31 | 1998-08-05 | SHARP Corporation | Diffractive spatial light modulator |
| DE10102723A1 (en) * | 2001-01-22 | 2002-08-22 | Zeiss Carl | Beam deflector, switching arrangement with beam deflector and method for optionally linking connections for optical signals |
| EP3107153A1 (en) * | 2015-06-15 | 2016-12-21 | The Boeing Company | Liquid crystal filled antenna assembly, system, and method |
| CN108493592A (en) * | 2018-05-03 | 2018-09-04 | 京东方科技集团股份有限公司 | Microstrip antenna and preparation method thereof and electronic equipment |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4639091A (en) * | 1983-02-25 | 1987-01-27 | Thomson-Csf | Static deflector device for an infrared beam |
-
1988
- 1988-11-09 GB GB8826251A patent/GB2225122B/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4639091A (en) * | 1983-02-25 | 1987-01-27 | Thomson-Csf | Static deflector device for an infrared beam |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0519772A1 (en) * | 1991-06-18 | 1992-12-23 | Thomson-Csf | Microwave antenna with optoelectronical controlled scanning |
| FR2678112A1 (en) * | 1991-06-18 | 1992-12-24 | Thomson Csf | MICROWAVE ANTENNA WITH OPTOELECTRONIC SCANNING. |
| US5262796A (en) * | 1991-06-18 | 1993-11-16 | Thomson - Csf | Optoelectronic scanning microwave antenna |
| EP0856767A2 (en) * | 1997-01-31 | 1998-08-05 | SHARP Corporation | Diffractive spatial light modulator |
| EP0856767A3 (en) * | 1997-01-31 | 1999-03-24 | Sharp Kabushiki Kaisha | Diffractive spatial light modulator |
| US6091463A (en) * | 1997-01-31 | 2000-07-18 | Sharp Kabushiki Kaisha | Diffractive spatial light modulator |
| DE10102723A1 (en) * | 2001-01-22 | 2002-08-22 | Zeiss Carl | Beam deflector, switching arrangement with beam deflector and method for optionally linking connections for optical signals |
| EP3107153A1 (en) * | 2015-06-15 | 2016-12-21 | The Boeing Company | Liquid crystal filled antenna assembly, system, and method |
| US9553364B2 (en) | 2015-06-15 | 2017-01-24 | The Boeing Company | Liquid crystal filled antenna assembly, system, and method |
| CN108493592A (en) * | 2018-05-03 | 2018-09-04 | 京东方科技集团股份有限公司 | Microstrip antenna and preparation method thereof and electronic equipment |
| CN108493592B (en) * | 2018-05-03 | 2019-12-20 | 京东方科技集团股份有限公司 | Microstrip antenna, preparation method thereof and electronic equipment |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8826251D0 (en) | 1989-05-17 |
| GB2225122B (en) | 1992-12-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4706094A (en) | Electro-optic beam scanner | |
| EP0363084B1 (en) | Deflector for an optical beam | |
| US4937539A (en) | Phased array for optical beam control | |
| EP0501824B1 (en) | Optical beam steerer having subaperture addressing | |
| US5151814A (en) | Phased array for optical beam control | |
| US5061048A (en) | Apparatus for optical beam steering using non-linear optical polymers | |
| EP0377498B1 (en) | Deflector for an optical beam including refractive means | |
| US4447815A (en) | Lens for electronic scanning in the polarization plane | |
| US6456419B1 (en) | Frequency modulated liquid crystal beamsteering device | |
| US7903040B2 (en) | Tunable arrangements | |
| Matic | Blazed phase liquid crystal beam steering | |
| CN110275364B (en) | Heterogeneous integrated two-dimensional optical phased array | |
| US6317251B1 (en) | Thin film electro-optic beam steering device | |
| US4348075A (en) | Bulk acoustic wave integrated optical deflector and monolithic A/D converter using such deflector | |
| EP0331462A1 (en) | Liquid crystal cell window | |
| US4323901A (en) | Monolithic, voltage controlled, phased array | |
| US4693561A (en) | Amorphous silicon spatial light modulator | |
| EP1373977B1 (en) | Device for steering a beam of light | |
| EP0352302B1 (en) | Phase controlled light deflector | |
| Li et al. | Development of beam steerable reflectarray with liquid crystal for both E-plane and H-plane | |
| GB2225122A (en) | An apparatus for producing a phase shift in a beam of electromagnetic radiation | |
| US20230027067A1 (en) | Electrically-controlled dynamic optical component comprising a planar metasurface | |
| CN111403910B (en) | Terahertz reflection type two-dimensional scanning array antenna | |
| EP0027551A1 (en) | CCD driven integrated optical modulator array | |
| CN100365471C (en) | Optical phase array device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 746 | Register noted 'licences of right' (sect. 46/1977) |
Effective date: 19950613 |
|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20031109 |