Ruggedised GaAs FET amplifiers for military applications

The Gallium Arsenide Field Effect Transistor is finding broader application, and its performance is continually being improved. As a result, reliable, miniature, high-performance amplifiers must be designed, which will meet exacting electrical specifications, while performing under rigorous military environmental conditions. Ultimate performance will always be achieved with chip devices, and a diverse range of packaged devices are also available for users with limited technology. Limiters using simple shunt NIPs and Schottky barrier diodes are used to protect the device against leakage. Substrates are mounted on metal carriers, whose material is determined by thermal and electrical properties and how readily the material can be plated. The enclosure housing the amplifier assembly should also have hermetic capabilities. RF hermetic connectors provide a leakage rate of less than 0.00001 atmosphere cc/sec of helium, give excellent electrical performance to 18 GHz with minimal loss, and provide a stress relieved sliding contact to the microstrip substrates.