Other

United Kingdom Atomic Energy Authority

Parmeko Limited

James H Stephen

John D McCann

James A Cairns

Michael A Flemming

A substrate for use in the manufacture of electronic devices, comprising a lamina made of an aluminum-bearing ferritic steel coated with an adherent layer of a material having a high dielectric strength, a low dielectric constant and a co-efficient of thermal expansion approximately equal to that of the steel lamina.

Substrates for electronic devices

A surveillance system transmits a microwave carrier signal through a surveillance zone (14). Two low frequency energy fields are also established in the zone being produced by respective pairs of closely spaced apart low frequency signals radiated from opposite sides of the zone. A receptor reradiator in the zones receives these signals and reradiates a reply signal to a receiver the reply signal consisting of the microwave carrier signal amplitude modulated in accordance with the instantaneous value of the low frequency fields at the location of the receptor reradiator. The receiver separates out preselected intermodulation products and activates an alarm only when the preselected intermodulation products are present.

Surveillance systems

This invention is directed to a receptor reradiator for use in a system for detecting the position of the receptor reradiator in a surveillance zone. It comprises a first aerial means for receiving the first signal, second aerial means for radiating said reply signal and a non-linear element coupling the first and second aerial means.

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Abingdon, United Kingdom

James H Stephen