Scanning continuous antenna reflector device
First Claim
1. A method for obtaining a continuous aperture scanning antenna reflector element comprising the steps of:
- arranging a reflector element in the form of a plate of a material presenting ferroelectric properties;
arranging a first electromagnetically transparent, highly resistive film onto a first side of the plate of material presenting ferroelectric properties, the first highly resistive film at two opposite edges provided with a first and second highly conductive wire electrically connected along the respective opposite edge;
arranging a second electromagnetically transparent, highly resistive film onto a second side of the plate of material presenting ferroelectric properties, the second highly resistive film at two opposite edges provided with a third and fourth highly conductive wire electrically connected along the respective opposite edge, said third and fourth conducting wires of said second highly resistive film running perpendicular to said first and second wires of said first highly resistive film;
arranging a conducting reflector layer underneath said second highly resistive film, said reflector layer being insulated from said second film by an insulating layer;
connecting a first variable voltage source Ux to said first and second conducting wires of said first highly resistive film forming a static potential gradient across said first highly resistive film, and connecting a second variable voltage source Uy to said third and fourth highly conductive wires of said second highly resistive film to create a static potential gradient across said second highly resistive film, thereby forming perpendicular static E-fields across the plate;
illuminating said plate of material presenting ferroelectric properties carrying said first and second transparent highly resistive films with a microwave field of an arbitrary polarization, controlling the dielectric constant across the plate by controlling the voltages of said first and second voltage sources to thereby control a direction of an antenna lobe generated from reflected microwave power by means of the created scanning reflector antenna element.
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Abstract
A method and a device are disclosed for the generation of a surface, the reflection phase gradient of which will be varied by means of a controllable static electric field. The present solution takes into account, instead of mainly the transmissive properties, also the reflection properties of an arrangement comprising a ferroelectric material. Such a reflecting surface may contribute to an entire antenna aperture, a portion of an antenna aperture or an element in a conventional array aperture. In a general case N lobes and M nulls are to be controlled at the same time. In such a case the surface will preferably be designed as a curved surface, for instance a rotation symmetric parabola, while in other cases the reflector element may be designed just as a plane mirror. An antenna comprising such a reflector element of ferroelectric material can also form a polarization twisting Cassegrain antenna with a flat or curved main reflector element. The reflector element in a typical embodiment consists of a plate (50) of a material presenting ferroelectric properties and provided on each side with electromagnetically transparent highly resistive films (24, 34) each fed by means of a pair of parallel highly conducive edge wires (22, 23 and 32, 33). By applying a controllable voltage across each pair wires the lobe of the continuous aperture scanning reflector antenna can be controlled in a plane X-Z by a voltage Ux and in a plane Y-Z by a voltage Uy.
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Citations
10 Claims
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1. A method for obtaining a continuous aperture scanning antenna reflector element comprising the steps of:
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arranging a reflector element in the form of a plate of a material presenting ferroelectric properties;
arranging a first electromagnetically transparent, highly resistive film onto a first side of the plate of material presenting ferroelectric properties, the first highly resistive film at two opposite edges provided with a first and second highly conductive wire electrically connected along the respective opposite edge;
arranging a second electromagnetically transparent, highly resistive film onto a second side of the plate of material presenting ferroelectric properties, the second highly resistive film at two opposite edges provided with a third and fourth highly conductive wire electrically connected along the respective opposite edge, said third and fourth conducting wires of said second highly resistive film running perpendicular to said first and second wires of said first highly resistive film;
arranging a conducting reflector layer underneath said second highly resistive film, said reflector layer being insulated from said second film by an insulating layer;
connecting a first variable voltage source U x to said first and second conducting wires of said first highly resistive film forming a static potential gradient across said first highly resistive film, and connecting a second variable voltage source Uy to said third and fourth highly conductive wires of said second highly resistive film to create a static potential gradient across said second highly resistive film, thereby forming perpendicular static E-fields across the plate;
illuminating said plate of material presenting ferroelectric properties carrying said first and second transparent highly resistive films with a microwave field of an arbitrary polarization, controlling the dielectric constant across the plate by controlling the voltages of said first and second voltage sources to thereby control a direction of an antenna lobe generated from reflected microwave power by means of the created scanning reflector antenna element. - View Dependent Claims (2, 3, 4)
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5. A continuous aperture scanning antenna reflector device comprising a reflector element in the form of a plate of a material presenting ferroelectric properties;
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a first electromagnetically transparent, highly resistive film onto a first side of the plate of material presenting ferroelectric properties, said first highly resistive film at two opposite edges provided with a first and second highly conductive wire electrically connected along the respective opposite edge;
a second electromagnetically transparent, highly resistive film onto a second side of the plate of material presenting ferroelectric properties, said highly resistive film at two opposite edges provided with a third and a fourth highly conductive wire electrically connected along the respective opposite edge, said third and fourth conducting wires of said second highly resistive film then running perpendicular to said first and second highly conducting wires of said first highly resistive film;
a conducting reflector layer underneath said second highly resistive film, said reflector layer being insulated from said second highly resistive film by an insulating layer; and
a first variable voltage source U x is connected to said first and second conducting wires of said first electromagnetically transparent, highly resistive film forming a static potential gradient across said first highly resistive film, and a second variable voltage source Uy is connected to said third and fourth highly conductive wires of said second electromagnetically transparent, highly resistive film to create a static potential gradient across said second highly resistive film, thereby forming perpendicular static E-fields across the plate; and
whereina first side of the plate of material presenting ferroelectric properties covered by said first highly resistive film being illuminated with a microwave source having an arbitrary polarization, whereby a dielectric constant across the reflector element is controlled by means of the voltage of said first and second voltage sources and thereby controlling a direction of an antenna lobe generated from reflected microwave power by means of the created scanning reflector antenna element. - View Dependent Claims (6, 7, 8, 9, 10)
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Specification