Avalanche Diode Sources and Amplifiers.

The significance of this research and development to the Air Force is the extension of the operational range of high-efficiency silicon avalanche diodes from the original L-band into the S-, C-, X-, and Ku-bands and from the oscillator mode to the amplifier mode, a capability that did not previously exist, thus making the device a practical one for microwave systems application. The high output powers obtained from these diodes have met the major program requirements. The most outstanding result was a record 600-W output power at a 33 efficiency from a single-chip diode. A variety of circuits coaxial, microstrip, and waveguide was developed, including a novel antiparallel-microstrip circuit which looks very promising for combining power output of multiple diodes with improved heat-sinking. Another new technique which produces oscillation at higher frequencies through harmonic extraction was established from S- to Ku-band. Recent pulsed power outputs of 110 W in X-band and 68 in Ku-bands were found to be superior in device technology in duty cycle to those obtained with LSA devices. The feasibility of power amplification with avalanche diodes operating in the high-efficiency mode was also demonstrated in L-, S-, and X-bands. Author