Solid state components adapt to sensor environmental demands

Advances in the technology of all-weather sensor systems relying on solid state components operating at microwave frequencies are discussed. Gunn diodes, IMPATT diodes, and GaAs FETs are discussed in terms of their composition, power requirements, efficiency, reproducibility, and noise levels. Their use in various electronic systems, including oscillators, transmitters, double-drift devices, amplifiers, and phase arrays is considered. GaAs FETs are treated in more detail than the diodes, emphasizing parameters such as gate length, the use of exotic construction techniques to accommodate conflicting demands for both small dimensions for high frequency operations versus maintaining low power densities and hence low channel temperatures. Techniques for improving the yield of GaAs FETs are addressed, as well as methods of reducing the size and cost of microwave circuits that use those devices.