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Millimeter wave imaging sensors, sources and systems

  • US 5,202,692 A
  • Filed: 04/17/1991
  • Issued: 04/13/1993
  • Est. Priority Date: 06/16/1986
  • Status: Expired due to Term
First Claim
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1. A millimeter wave imaging sensor, comprising:

  • an array of sensing elements, each comprising an antenna element consisting of a pair of conductive elements, said conductive elements being adapted to detect millimeter wave radiation, and a nonlinear circuit element connected across each pair of conductive elements for rectifying millimeter wave radiation detected by said pair of conductive elements; and

    means for focusing millimeter wave radiation from a field of view onto said array, said means for focusing being aligned along an optical axis with said array of sensing elements;

    an oscillator for emitting linearly-polarized millimeter-wave radiation, disposed off said optical axis;

    a polarizing grid on said optical axis for dividing said radiation emitted by said oscillator into major and minor components, and for directing said major component of said radiation into the field of view, said minor component of said radiation passing through said polarizing grid; and

    means for rotating the polarization of said minor component and reflecting it onto said polarizing grid, whereby said polarizing grid reflects said minor component onto said array of sensing elements as a local oscillator signal.

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