National Academies Press: OpenBook

Summary of the Sensing and Positioning Technology Workshop of the Committee on Nanotechnology for the Intelligence Community: Interim Report (2004)


Suggested Citation:"NANOSCALE DESIGN AND FABRICATION CONSIDERATIONS FOR PHOTONIC TAGS AND RADAR DEVICES." National Research Council. 2004. Summary of the Sensing and Positioning Technology Workshop of the Committee on Nanotechnology for the Intelligence Community: Interim Report. Washington, DC: The National Academies Press. doi: 10.17226/11032.
Page 20

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

RADIO/RADAR/OPTICAL TAGS 20 it could be used by ground-based friendly forces to communicate covertly with radar systems on aircraft. A simple message (e.g., 30 bits) could be coded into the PARD and read by a VESTA radar system passing overhead without the message being detectable to hostile forces. COVERT RADAR TAGS AND APPLICATIONS Bill Hurley discussed his company's technology, which involves incorporating a large number of radar reflectors in a substrate to form passive RFID tags. The radar reflectors used by Inkode are usually simple aluminum fibers that form half-wave resonators within the object to be tracked (e.g., a piece of paper). The radar- reflecting fibers are approximately the same diameter as paper fibers (typically 6.5 mm long and 1.5 µm in diameter). Randomly oriented radar-reflecting fibers provide a unique backscatter pattern that can be read and stored in a database for future identification. Ordered patterns can also be designed so that individual resonators are coupled or decoupled, whatever is likely to give the optimum backscatter pattern. Tagging an object with this technology costs about 1 cent. When illuminated with radar, the backscattered fields interact to create a unique interference pattern that enables one tagged object to be identified and differentiated from other tagged objects. In the near field (that is, where there is an interaction between the tag and antenna), the backscatter depends on the position of the tag in the substrate, and information is represented in a scalar waveform. Beyond the near field, the backscatter is like a traditional radar, with no coupling between tag and antenna. For nonmilitary applications, the reader is less than 1 meter from the tag. For military applications, the reader and tag could theoretically be separated by a kilometer or more. The tags are the same in these two cases, but the reader is different. The normal operating point is 10 mW at 24 GHz. The three most commonly used tags are free, individual resonators, continuous filaments, and photolithographically printed patterns of filaments. They consist of aluminum/glass fibers, either coaxial or side by side. These may be adapted for inclusion in a variety of objects, including paper, airline baggage tags, book bindings, clothing and other fabrics, and plastic sheet. The reflectance of the half-wave resonators is very efficient. In a typical 8½ by 11 inch piece of paper, there are over 8,000 radar reflecting fibers. This can theoretically be seen from a distance comparable to the distance from which a 1 m2 target can be seen. NANOSCALE DESIGN AND FABRICATION CONSIDERATIONS FOR PHOTONIC TAGS AND RADAR DEVICES Dennis Prather discussed applications of nanoscale photonics technology and some of the tools being developed to fabricate these devices. Applications include (1) diffractive (as opposed to refractive) lenses that can reduce the size and weight of millimeter wave imaging systems; (2) polarization-dependent tags or reflectors that can be read with a CO2 laser; (3) integrated sensors using components made from photonic crystal devices— that is, devices that guide light based on the scattering properties created by tailoring the material profile—such as beam splitters, optical switches, and couplers; and (4) motion microsensors, both rotational and linear. The beam routing in photonic crystal devices is strongly wavelength-dependent; for instance, such devices exhibit a sharp spike in reflectivity over a narrow frequency bandgap. This property can be exploited in photonic tags. Prather discussed the capabilities of various fabrication methods for creating nanoscale patterned structures, such as e-beam and interferometric lithography, methods for optical drilling of nanoscale cylindrical holes through silicon, and techniques for making tapered connectors to link microscale

Summary of the Sensing and Positioning Technology Workshop of the Committee on Nanotechnology for the Intelligence Community: Interim Report Get This Book
Buy Paperback | $21.00 Buy Ebook | $16.99
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

The emergence of nanotechnology as a major science and technology research topic has sparked substantial interest by the intelligence community. In particular the community is interested both in the potential for nanotechnology to assist intelligence operations and threats it could create. To explore these questions, the Intelligence Technology Innovation Center asked the National Research Council to conduct a number of activities to illustrate the potential for nanotechnology to address key intelligence community needs. The second of these was a workshop to explore how nanotechnology might enable advances in sensing and locating technology. This report presents a summary of that workshop. In includes an overview of security technologies, and discussions of systems, natural chemical/biological tags, passive chemical/biological tags, and radio/radar/optical tags.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook,'s online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!