Multibeam optical and electromagnetic hemispherical/spherical sensor
First Claim
1. A lens comprising a plurality of concentric dielectric shells of aerogel material, arranged around a center sphere of material characterized by a refractive index of approximately √
- 2, and wherein said lens has an outer radium ro, and the radius of each shell is characterized by a typical radium value r, the respective refractive index value of each shell being an approximation to the formula (2-(r/ro)2)1/2, said lens characterized in that planar electromagnetic wave fronts incident on said lens from a distant source are imaged at a focus point on the lens surface at the end of the diameter of the lens in the direction of the incoming wave front and that the lens provides electro-optical and radio frequency operation.
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Accused Products
Abstract
An optical spherical Luneburg lens is described which is also useful for millimeter wave and microwave operation, which can provide a multitude of simultaneously acting receiving beams over a hemispherical or spherical field of view. When used in conjunction with surface mounted optical/radio frequency pickup elements, the lens can be employed in a passive target detection system of unique field of coverage and sensitivity. The lens comprises a center sphere of refractive index of approximately √2, around which are arranged in concentric shells of aerogel material. The aerogel material of the respective shells is fabricated to obtain a particular index of refraction approximately equal to (2-(r/r0)2)1/2, where r is the radius of the shell and r0 is the radius of the lens assembly. The lens can be employed in a system providing dual mode simultaneous optical and radio frequency operation with a single aperture. Its multibeam simultaneous detection capability can provide an input to advanced digital signal processors to perform automatic image and pattern recognition for commercial and military sensor systems. It may also be used as an active sensor using optical or radio frequency energy.
51 Citations
29 Claims
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1. A lens comprising a plurality of concentric dielectric shells of aerogel material, arranged around a center sphere of material characterized by a refractive index of approximately √
- 2, and wherein said lens has an outer radium ro, and the radius of each shell is characterized by a typical radium value r, the respective refractive index value of each shell being an approximation to the formula (2-(r/ro)2)1/2, said lens characterized in that planar electromagnetic wave fronts incident on said lens from a distant source are imaged at a focus point on the lens surface at the end of the diameter of the lens in the direction of the incoming wave front and that the lens provides electro-optical and radio frequency operation.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A sensor system comprising:
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a spherical lens comprising a plurality of concentric dielectric shells of aerogel material, arranged around a center sphere of material characterized by a refractive index of approximately √
2, and wherein said lens has an outer surface radius of ro, and wherein each shell is characterized by a typical radius value r, the respective refractive index value of each shell being approximately equal to (2-(r/ro)2)1/2, said lens being characterized in that planar electromagnetic wave fronts incident on said lens from a distance source are imaged at a point on the lens surface at the end of the diameter of the lens in the direction of the incoming wave fronts and that the lens provides electro-optical and radio frequency operation;a plurality of sensor elements each responsive to the energy imaged at a desired focus point on the external surface of said lens and providing an electrical signal indicative of the beam energy imaged at the focal point; and signal processing means responsive to the sensor electrical signals for processing said signals. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A radar system comprising:
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a spherical lens comprising a plurality of concentric dielectric shells of aerogel material, arranged around a center sphere of material characterized by a refractive index approximately √
2 and wherein said lens has an outer radius of ro, and wherein the radius of each shell is characterized by a typical radius value r, the respective refractive index value of each shell being approximately equal to (2-(r/ro)2)1/2, said lens characterized in that planar electromagnetic wave fronts incident on said lens from a distant source are imaged at a focus point on the lens surface at the end of the diameter of the lens in the direction of the incoming wave fronts and that the lens provides electro-optical and radio frequency operation;a plurality of radio frequency energy transducers located at a plurality of focus points about at least a portion of the external surface of the lens, said energy transducers for converting radio frequency energy received at said focus points into electrical signals and vice versa; a transmitter coupled to said transducers for selectively exciting one or more of the transducers to produce one or more transmit beams, each corresponding to a particular transducer; and a receiver and signal processor coupled to said transducer to selectively receive return signals from one or more transducers and process said signals. - View Dependent Claims (21, 22, 23)
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24. A sensor system comprising:
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a spherical lens comprising a plurality of concentric dielectric shells of aerogel material, arranged around a center sphere of material characterized by a refractive index approximately √
2 and wherein said lens has an outer radius of ro, and wherein the radius of each shell is characterized by a typical radius value r, the respective refractive index value of each shell being approximately equal to (2-(r/ro)2)1/2, said lens characterized in that planar electromagnetic wave fronts incident on said lens from a distant source are imaged at a focus point on the lens surface at the end of the diameter of the lens in the direction of the incoming wave fronts;a plurality of optical sensors located at a plurality of sensor focus points about at least a portion of the external surface of the lens, said energy transducer for converting optical energy into electrical signals indicative of energy received at said focus points; a plurality of optical transducers for emitting light energy at particular transmit focus points dispersed among said sensor focus points for emitting optical light energy in response to electrical transducer signals; a transmitter comprising means for generating said electrical transducer signals for selectively exciting one or more of the transducers to produce one or more transmit beams, each corresponding to a particular transducer; and a receiver and signal processor coupled to said optical sensors to selectively receive signals from one or more sensor elements and process said signals. - View Dependent Claims (25, 26, 27, 28, 29)
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Specification