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Proceedings Paper

Terahertz coded aperture mask using vanadium dioxide bowtie antenna array
Author(s): Souheil Nadri; Rebecca Percy; Lin Kittiwatanakul; Alex Arsenovic; Jiwei Lu; Stu Wolf; Robert M. Weikle II
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Paper Abstract

Terahertz imaging systems have received substantial attention from the scientific community for their use in astronomy, spectroscopy, plasma diagnostics and security. One approach to designing such systems is to use focal plane arrays. Although the principle of these systems is straightforward, realizing practical architectures has proven deceptively difficult. A different approach to imaging consists of spatially encoding the incoming flux of electromagnetic energy prior to detection using a reconfigurable mask. This technique is referred to as coded aperture"or Hadamard"imaging. This paper details the design, fabrication and testing of a prototype coded aperture mask operating at WR-1.5 (500-750 GHz) that uses the switching properties of vanadium dioxide(VO2). The reconfigurable mask consists of bowtie antennas with vanadium dioxide VO2 elements at the feed points. From the symmetry, a unit cell of the array can be represented by an equivalent waveguide whose dimensions limit the maximum operating frequency. In this design, the cutoff frequency of the unit cell is 640 GHz. The VO2 devices are grown using reactive-biased target ion beam deposition. A reflection coefficient (S11) measurement of the mask in the WR-1.5 (500-750 GHz) band is conducted. The results are compared with circuit models and found to be in good agreement. A simulation of the transmission response of the mask is conducted and shows a transmission modulation of up to 28 dB. This project is a first step towards the development of a full coded aperture imaging system operating at WR-1.5 with VO2 as the mask switching element.

Paper Details

Date Published: 5 September 2014
PDF: 9 pages
Proc. SPIE 9199, Terahertz Emitters, Receivers, and Applications V, 91990C (5 September 2014); doi: 10.1117/12.2060899
Show Author Affiliations
Souheil Nadri, Univ. of Virginia (United States)
Rebecca Percy, Univ. of Virginia (United States)
Lin Kittiwatanakul, Univ. of Virginia (United States)
Alex Arsenovic, Virginia Diodes, Inc. (United States)
Jiwei Lu, Univ. of Virginia (United States)
Stu Wolf, Univ. of Virginia (United States)
Robert M. Weikle II, Univ. of Virginia (United States)

Published in SPIE Proceedings Vol. 9199:
Terahertz Emitters, Receivers, and Applications V
Manijeh Razeghi; Alexei N. Baranov; John M. Zavada; Dimitris Pavlidis, Editor(s)

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