High efficiency pulsed GaAs Read impatt diodes

GaAs Read impatt diodes have been developed for pulsed operation in X and Ku bands. Conversion efficiencies of 32% and 29% have been measured for p+n+n¿n+ (high-low) doping profiles grown by liquid phase and vapour phase epitaxy, respectively. Peak powers of 30 W in X band and 20 W in Ku band have been obtained with single mesas on gold plated heatsinks. Multiple mesas in parallel and diamond heatsinking were employed to improve thermal resistance. Microwave circuit and chip level power combining techniques were also investigated and greater than 90% combining efficiency was achieved on the chip level.