Metal detectors currently used for screening aircraft passengers could soon be supplanted by novel millimeter-wave cameras, able to detect even non-metallic concealed objects. The new system, named after a Brazilian bat, is based on technology developed for European Space Agency (ESA) spacecraft. Tadar was demonstrated at the recent Inter Airport Europe Exhibition in Munich, Germany.
Conventional metal detectors, such as those used to check passengers at airports, are limited in that they can only detect metal objects. Other security technologies such as the X-ray imaging used to screen luggage, are unsuitable for checking people because of their use of ionizing radiation.
An Irish company has now come up with a new security imaging system that can "see" all objects, not just metallic items, by the use of only safe natural energy. Named Tadar, after the Brazilian Tadarida bat, it uses millimeter-waves to detect and identify suspicious objects hidden under clothing or to see through cloud and fog, in the same way that the bat uses high-frequency signals to navigate and locate insect prey in the dark. The high-frequency energy pulses emitted by the bat bounce off objects in its path, and the reflected signals are interpreted by different types of sensory cells in the bat's brain to determine both the location and physical properties of these objects.
"This new system is based on advanced microwave technology that Farran, now part of the Smith Group, has developed for space systems," explains Tony McEnroe, managing director of Farran Technology. "We developed the knowledge and skills while designing and packaging millimeter-wave devices for ESA projects. By integrating a novel scanning technology we have achieved a unique system for detecting and imaging items for security applications."
Tadar's sensors detect energy naturally emitted or reflected from objects, by using approximately 3-mm wavelengths that are completely harmless to people. At this wavelength, clothes become transparent, but dense objects, such as explosives and weapons hidden under clothing, block the body's natural radiation and reflect a clear profile of the blocked energy field.
Door keys, money, pocket knives, and other objects that we normally carry in our pockets will stand out clearly. Even weapons produced in non-metallic materials and plastic explosives which conventional metal detectors cannot "see," will clearly be identified, as well as liquid substances. Each type of material has its own frequency response and will produce its own representative "color" image, almost like a fingerprint.
High-frequency space components for new security system
Founded in 1977, Farran Technology has been supplying ESA for years with high-frequency microwave components and subsystems. Since 1998, the improved materials used for integrated circuits have permitted the production of integrated circuit devices able to operate within the millimeter-wave spectrum--the 30-300 GHz range of the frequency spectrum--used for a broad range of applications from advanced astronomy to broadband radio communications.
This advance enabled Farran to develop an in-house capability in the design and development of high-frequency circuits. …