Stealthy Wallpaper

Stealthy wallpaper is a practical material designed to control the transmission of RF signals. Manufactured in panels, it can be incorporated into properly screened rooms and acts as an rf window which can be turned on and off. This will allow independent control over the way communications equipment, such as computers operating with WiFi or cell phones, may be accessed. This has the potential to improve both the efficiency and security of these systems.

What has become known as 'stealthy wallpaper' is an active frequency selective surface (AFSS) which is very thin, light and acts as a planar band-pass rf filter working at sub-gigahertz and low gigahertz frequencies. The wallpaper, which is designed to have specified characteristics when incorporated into a properly designed shielded environment, allows the selective transmission of communications frequencies and has been demonstrated in a practical environment.

Selective transmission is achieved by switching the wallpaper on or off - corresponding to low or high transmission respectively. As examples, Wireless Local Area Networks (WLANs) and mobile cell phones have generated particular communications problems which could be solved using stealthy wallpaper.

• The efficiency of WLANs decrease as the number of users increase and mutual interference can degrade these systems to the point where they become unusable. Also, WLANs are not secure and gaining unauthorised assess to computer networks is relatively easy. The ability to control WLAN communications within a building, selection of offices or between buildings will become necessary as wired systems decline in popularity.
• The use of mobile phones, under certain circumstances can be a security risk, or just simply undesirable. There is scope here, for example, in keeping mobile phone frequency bands out of buildings or rooms while still retaining access emergency services.

Significant worldwide publicity and commercial interest has been generated, with two clear potential exploitation routes:

• The security market, including the improved security of WLAN based military communications systems.
• A consumer product aimed at the potentially much larger domestic market.