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Proceedings Paper

Further designs of optomechanical scanners for use in passive millimeter-wave imaging
Author(s): Alan H. Lettington; Dennis Dunn; Magdy F. Attia; Isaiah M. Blankson
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Paper Abstract

Mm-wave imaging has high potential for all weather performance but requires large apertures to acheive acceptable spatial resolution. These large apertures need to collect radiation from a range of angles in the field of view and form a two dimensional image. The ideal method for achieving such an image would be to have an aperture completely filled with receivers and to electronically beam-form. Unfortunately this technology is not sufficiently developed at present to make this a practical propostion. Receivers are far too expensive to form a completely filled aperture and the technology of beam-forming is still under development. The alternative and most cost effective solution at present is to have a comparatively small number of receivers and scan them across the scene using an opto-mechanical scanner. In scanned thermal imaging systems it is usual to employ high speed rotating polygons to perform the line scan and a flapping mirror for the framing motion. The pupil size is typically 10mm in thermal imaging and the polygons are 40mm in diamenter. If such an arrangement were used at mm-waves where the pupil size is of the order of 1m, the rotating polygon would be 4m in diameter. The paper describes new compact opto-mechanical systems based on rotating discs, prisms and using frequency and polarization selective surfaces.

Paper Details

Date Published: 20 August 2003
PDF: 11 pages
Proc. SPIE 5077, Passive Millimeter-Wave Imaging Technology VI and Radar Sensor Technology VII, (20 August 2003); doi: 10.1117/12.497570
Show Author Affiliations
Alan H. Lettington, Univ. of Reading (United Kingdom)
Dennis Dunn, Univ. of Reading (United Kingdom)
Magdy F. Attia, Johnson C. Smith Univ. (United States)
Isaiah M. Blankson, NASA Glenn Research Ctr. (United States)


Published in SPIE Proceedings Vol. 5077:
Passive Millimeter-Wave Imaging Technology VI and Radar Sensor Technology VII
Roger Appleby; Robert Trebits; David A. Wikner; James L. Kurtz, Editor(s)

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