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Optical Engineering

Design of 220 GHz electronically scanned reflectarrays for confocal imaging systems
Author(s): Abigail Hedden; Charles R. Dietlein; David A. Wikner
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Paper Abstract

The authors analyze properties of a 220 GHz imaging system that uses a scanned reflectarray to perform electronic beam scanning of a confocal imager for applications including imaging meter-sized fields of view at 50 m standoff. Designs incorporating reflectarrays with confocal imagers have not been examined previously at these frequencies. We examine tradeoffs between array size, overall system size, and number of achievable image pixels resulting in a realistic architecture capable of meeting the needs of our application. Impacts to imaging performance are assessed through encircled energy calculations, beam pointing accuracy, and examining the number and intensity of quantization lobes that appear over the scan ranges of interest. Over the desired scan range, arrays with 1 and 2-bit phase quantization showed similar array main beam energy efficiencies. Two-bit phase quantization is advantageous in terms of pointing angle error, resulting in errors of at most 15% of the diffraction-limited beam size. However, both phase quantization cases considered resulted in spurious returns over the scan range of interest and other array layouts should be examined to eliminate potential imaging artifacts.

Paper Details

Date Published: 18 May 2012
PDF: 11 pages
Opt. Eng. 51(9) 091611 doi: 10.1117/1.OE.51.9.091611
Published in: Optical Engineering Volume 51, Issue 9
Show Author Affiliations
Abigail Hedden, U.S. Army Research Lab. (United States)
Charles R. Dietlein, U.S. Army Research Lab. (United States)
David A. Wikner, U.S. Army Research Lab. (United States)

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