Classifications

• • 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
  • H01Q3/26—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 relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/08—Optical arrangements
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/02—Constructional details
  • G01J5/08—Optical arrangements
  • G01J5/0837—Microantennas, e.g. bow-tie
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/10—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q21/00—Antenna arrays or systems
  • H01Q21/06—Arrays of individually energised antenna units similarly polarised and spaced apart
  • H01Q21/061—Two dimensional planar arrays
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J2005/0077—Imaging

Definitions

• This disclosure relates generally to infrared detection systems. More particularly, to a detector which couples the antenna output directly into the sensor electronics in a phased scanning array, eliminating in one or more embodiments, the need for a photo detector and lens.
• Infrared (IR) detection sensors have a multitude of uses, from military purposes such as missile detection and imaging during nighttime combat operations, to civilian applications such as in the small handheld viewers that are often used by police and fire departments. Two concerns regarding IR imaging are the cost of the IR imaging system, and its weight.
• thermal type IR detection sensors can operate at room temperature (around 300 K), over a wide spectrum in the IR range, however these detectors lack fast response times needed for dynamic situations. The slower rate of speed makes “thermal type” IR detectors generally unable to compete in applications relating to missile detection and seeking, for example, and preclude them from many surveillance uses.
• the present application provides improvements over known IR detector systems, by eliminating, in one or more embodiments, the need for the sensor lens and aperture stop all together.
• the IR sensor may include an antenna, an antenna phase shifting device, and a transducer.
• IR radiation emitted from an object will create an antenna current within the antenna.
• the controllable phase shifting device will shift the phase of the antenna current, which in turn, will shift an antenna pattern that is associated with the antenna.
• the transducer will convert the antenna current received by the controlled antenna pattern into an electrical signal, representing at least a portion of an IR image associated with the object emitting the IR radiation.
• each IR sensor may have a pair of antenna arms, a phase shifting device, and a transducer.
• the pair of antenna arms are configured to receive IR radiation, where receipt of IR radiation would induce an antenna current.
• the phase shifting device coupled to at least one of the antenna arms, is configured to controllably shift a phase of the antenna current.
• the transducer coupled to the phase shifting device and at least one of the antenna arms, is configured to convert the antenna current into an electrical signal representing at least a portion of an IR image.
• the pair of antenna arms and the transducer cooperate to directly detect the IR radiation.
• the unit cells within each linear array are spatially arranged such that at least one antenna beam is formed.
• a phase controller configured to individually control the phase shifting device of each unit cell, so that the antenna beam or beams are directionally controllable.
• a readout circuit configured to process the electrical signal from each of the plurality of unit cells, provides an output representing at least a portion of a pixel of the IR image.
• Yet another embodiment of this disclosure relates to a method for IR imaging.
• the method requires forming at least one antenna beam by adjusting a phase of each of a plurality of IR sensors suitable for direct detection.
• the method then involves receiving IR radiation emitted from an object within the antenna beam or beams, and detecting antenna current or currents responsive to the IR radiation received by each antenna beam.
• the embodied method additionally contains scanning the antenna beam or beams in either an azimuth or elevation direction, or both.
• the method also entails converting the antenna current or currents into corresponding electrical signals, representing at least a portion of an IR image of the object. By additionally processing the electrical signal or signals, an output representing at least one pixel of an IR image of the object is created.
• FIG. 1 is a schematic view of an embodiment of a sensor
• FIG. 2 is a cutaway schematic view of an embodiment of a linear array of sensors
• FIG. 3 is a series of diagrams showing an embodiment of the progression of the scanning beam from a single linear array such as the embodiment in FIG. 2 as it is moved over the surface of a target object;
• FIG. 4 is a cutaway schematic view of an embodiment of a planar array comprising a plurality of linear arrays of the sensors of the present invention seen in the embodiment of FIG. 2;
• FIG. 5 is a series of diagrams showing an embodiment illustrating the progression of a plurality of scanning beams from a planar array (e.g., the embodiment in FIG. 4), as it is moved over the surface of a target object; and
• FIG. 6 is a series of diagrams showing an embodiment illustrating the progression of a single scanning beam from a planar array (e.g., the embodiment in FIG. 4) as it is moved over the surface of a target object.
• FIG. 1 shows a schematic view of an embodiment of an infrared (IR) sensor 100, suitable for direct detection of IR radiation that is being emitted from an object.
• IR sensor 100 contains an antenna 110, shown in the present embodiment as a dipole antenna with antenna arms.
• Antenna arms 110 of the illustrated embodiment are configured to receive IR radiation emitted from an object by inducing an antenna current.
• the antenna can be of any suitable construction or configuration, including but not limited to gold, aluminum, and/or tin.
• antenna current is carried from antenna 110 by IR transmission line 115, which may also be of any suitable construction or configuration including but not limited to gold or aluminum.
• IR sensor 100 additionally contains phase shifting device 120.
• Phase shifting device 120 is configured to selectively shift a phase of the antenna current, wherein the phase- shifted antenna current is used to shift an antenna pattern associated with antenna 110.
• Phase shifting device 120 can be of any number of constructions or configurations, including but not limited to a varactor diode, a ferrite, a PIN diode, or a MOS capacitor, for example.
• Phase shifting device 120 is seen in the illustrated embodiment as having control line 130, receiving commands from a phase controller (not shown).
• transducer 140 configured to convert antenna current within IR transmission line 115 into an electrical signal representing at least a portion of an IR image of the object.
• Transducer 140 can be any device suitable for converting antenna current into an electrical signal, and due to present ease of manufacturing and responsiveness, may be a forward biased Schottky diode.
• Other transducers that are capable of converting high frequency antenna current to an electrical signal may also be used, including but not limited to other such diodes, a thermal detector, a bolometer, a piezoelectric device, a rectifier, or a photo conductor.
• the electrical signal is carried through readout line 150 to a readout circuit (not shown).
• FIG. 2 illustrates an embodiment in which a plurality of IR sensors 100 are assembled in a linear array, with each of the illustrated plurality distinguished by ',", or * respectively.
• the center to center spacing of these IR sensors 100 allow for their phase adjusted antenna patterns to add constructively or destructively to form one or more antenna beams, focusing on a particular area of the target object that is emitting IR radiation.
• the antenna patterns are shifted in either an azimuth direction, an elevation direction, or both, depending on the particular imaging requirements.
• linear array 200 The scanning nature of linear array 200 is depicted in FIG 3, showing a schematic of a single linear array scanning individual areas of target 300, from area 301 to area 304. If linear array 200 is stationary, then the phase of individual antennae may be adjusted to shift the combined antenna pattern to scan elsewhere on target 300, converting the signals from the array for each phase setting into at least a single pixel of an image, and assembling the pixels generated from the scan into an image representing at least a portion of the target object 300 that is emitting the IR radiation.
• the linear array may be non-stationary, such as mounted underneath an airplane for ground imaging, wherein the linear array would only need to scan in a linear pattern, utilizing and compensating for the motion of the airplane to combine the repeating linear scans into a two dimensional image.
• this "push broom" array could constitute the entire wingspan of the airplane for increased image resolving power.
• FIG. 4 illustrates an embodiment in which a plurality of linear arrays 200 are assembled as a planar array 400, with each of the illustrated plurality of linear arrays 200 distinguished by ',", or * respectively.
• the direct imaging may be accomplished as depicted by FIG.
• the IR sensors of planar array 400 can be phase shifted to selectively receive IR radiation from a single area 310 of target object 300.
• individually controlling the phase of the IR sensors allows converting the combined signals from the array for each phase setting into at least a single pixel of an image, and assembling the pixels generated from the scan into an image representing at least a portion of the target object 300 that is emitting the IR radiation.
• Such a "super-pixel” embodiment would have the advantage of greater resolving power, and could still make use of the "push broom" array concept when utilizing the sensors on an airplane for ground imaging.
• a phased array (e.g., with 4x4 dipole elements in each conventional non-directional pixel) may be supported by a coherent power combiner (i.e., a 16-way power combiner in this example).
• a coherent power combiner i.e., a 16-way power combiner in this example.
• the above inventive concept finds utility in infrared detection systems. More particularly, utility is found in a detector that couples the antenna output directly into sensor electronics in a lens-less phased scanning array.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Variable-Direction Aerials And Aerial Arrays (AREA)
• Photometry And Measurement Of Optical Pulse Characteristics (AREA)
• Solid State Image Pick-Up Elements (AREA)

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• 2009
  • 2009-07-30 WO PCT/US2009/052241 patent/WO2010053608A2/en not_active Ceased
  • 2009-07-30 JP JP2011521318A patent/JP2012507691A/ja active Pending
  • 2009-07-30 EP EP09815440A patent/EP2318878A2/de not_active Withdrawn

Non-Patent Citations (1)

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