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New advances in detection and identification technology from Oxford University

July 01, 2002

Increasingly, industry demands technologies that enable detection and identification of targets, ranging from information for traffic tolling and airspace management to patient supervision in hospitals, security passes and stock control. Researchers at Oxford University's Department of Engineering Science have developed new retroreflectors that address that demand with potential application in detection, tracking, positioning and identification.

Present simple retroreflectors comprising corner structures are sometimes employed to increase the radar cross sections of targets like boats. However, these devices are limited as they do not lend themselves to modulation and therefore cause difficulty in establishing communications links. Current active transponders are costly and power-hungry, so they are unsuitable for many applications. Additionally, they are non-directional so the radio frequency transponders cause environmental pollution.

The Oxford invention consists of retroreflectors that reflect signals back to their source. A retroreflector for microwave frequencies and a retroreflector for the optical range have been developed. Generically, the microwave device will be used for longer-range applications such as vehicle monitoring, and the optical system will be suitable for smartcards for use in PDAs or 'personal' information carriers.

The microwave retroreflector comprises a flat array structure where antennas, switches and connections are all contained on a single printed circuit providing a cheap, robust and visually unobtrusive unit. The benefit of the new optical retroreflector is a return signal that can be modulated to provide a means of transmitting data relating to identification, position, and speed, among others. The ability to pick out coded returns may be used to enhance the readability of a display, enabling detection within any background clutter. Since the incident radiation is retroreflected, rather than retransmitted, the only electrical power necessary is that required to drive the optional solid state modulation switches, achieved from a modest power source such as small battery or solar cell.

Isis Innovation, Oxford University's technology transfer company, already has an agreement in place for marine applications, but opportunities are still available for companies interested in developing the microwave technology in other available fields and those interested in utilising the optical technology.

Isis Innovation Ltd