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Stealthy wallpaper Novel interior decoration for wireless security
What do a stealth bomber and your four walls have in common? At the moment almost nothing, but this may change soon. A spin-off from stealth aircraft radar signature control technology is ready to innovate the interior design of high-tech offices and paranoid-geek homes. British defence company BAE Systems has developed a “stealthy wallpaper” which is designed to block uninvited radio transmissions. What differentiates the “stealthy wallpaper” from conventional barriers against radio waves – like, for instance, frequency-absorbing foam or metal – is its ability to filter frequencies. This allows you to receive a mobile phone call while your Wireless LAN is blocked. Frequency selective surface The trick is done by a frequency selective surface (FSS), which is very thin – 50 to 100 microns (millionth of a meter). BAE Systems designed several types of FSS. One is aimed at blocking WLAN transmissions while permitting signals in the UMTS bands to pass through. Other designs permit passbands corresponding to the IEEE802.11b and IEEE802.11a communications standards to be enabled and disabled at the touch of a button. The material can be applied to ordinary structural and partition walls. For application to windowpanes, transparent conductors can be used.
Military spin-off The basic principles of the frequency selective surface are identical to those of materials used in aircraft radar signature reduction. Where the “stealthy wallpaper” differs is that it is not incorporated into a structural radome and is a thin, flexible material. It does not require the addition of extra dielectric layers to preserve its characteristics at high incidence angles or provide a sharp filter response. Work on the project began in May 2003 and culminated in a full-scale demonstration in May 2004. The short development time is easily explained: the team working on the “stealthy wallpaper” project has more than 25 man years experience in the field of frequency selective surfaces. Commercial use Kevin Mitchell, project manager at BAE Systems Advanced Technology Centre, Filton, envisages two major applications: “Firstly, isolation of WLAN transmissions for enhanced network security. Secondly, control of WLAN signals with the aim of reducing interference and hence allowing more networks to exist in close proximity.” In the initial marketing phase, he expects large corporations who want to improve the security of their wireless networks to be the main customers. “The domestic consumer market may follow, particularly if wireless technology is widely adopted in areas of high-density housing, and interference between networks becomes significant,” said Mr Mitchell. Regarding the cost, BAE Systems claims that their “stealthy wallpaper” is no more expensive than conventional methods of screening, because only conventional PCB materials and manufacturing processing need to be used. BAE Systems is currently exploring how best to bring the product to the market. This may involve licensing designs, a spin-off company or some form of partnership with an existing operator in the civil communications field, according to Mr Mitchell. There is no planned launching date yet, but Mr Mitchell is confident that “given the maturity of the technology, it is possible that a product may be commercially available in a short timescale.”
Until this happens, the best remedy to protect your Wireless LAN against nosy neighbours and worrisome wardrivers, who want to eavesdrop on your data communication, will be to get your WEP (Wired Equivalent Privacy) settings rights. Please send us your comments on this article. |
