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Proceedings Paper

Imaging terahertz radar for security applications
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Paper Abstract

Detection of concealed threats is a key issue in public security. In short range applications, passive imagers operating at millimeter wavelengths fulfill this task. However, for larger distances, they will suffer from limited spatial resolution. We will describe the design and performance of 0.8-THz imaging radar that is capable to detect concealed objects at a distance of more than 20 meter. The radar highlights the target with the built-in cw transmitter and analyses the returned signal making use of a heterodyne receiver with a single superconducting hot-electron bolometric mixer. With an integration time of 0.3 sec, the receiver distinguishes a temperature difference of 2 K at the 20 m distance. Both the transmitter and the receiver use the same modified Gregorian telescope consisting from two offset elliptic mirrors. The primary mirror defines limits the lateral resolution of the radar to 2 cm at 20 m distance. At this distance, the field of view of the radar has the diameter 0.5 m. It is sampled with a high-speed conical scanner that allows for a frame time less than 5 sec. The transmitter delivers to the target power with a density less than ten microwatt per squared centimeter, which is harmless for human beings. The radar implements a sensor fusion technique that greatly improves the ability to identify concealed objects.

Paper Details

Date Published: 15 April 2008
PDF: 11 pages
Proc. SPIE 6949, Terahertz for Military and Security Applications VI, 694902 (15 April 2008); doi: 10.1117/12.778477
Show Author Affiliations
Alexei Semenov, DLR Institute of Planetary Research (Germany)
Heiko Richter, DLR Institute of Planetary Research (Germany)
Ute Böttger, DLR Institute of Planetary Research (Germany)
Heinz-Wilhelm Hübers, DLR Institute of Planetary Research (Germany)


Published in SPIE Proceedings Vol. 6949:
Terahertz for Military and Security Applications VI
James O. Jensen; Hong-Liang Cui; Dwight L. Woolard; R. Jennifer Hwu, Editor(s)

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