VOLUNERABILITY EFFECTS IN BULK-SOLIDS. VOLUME II. OPERATION OF GUNN DEVICES IN A SERIES D-C BIAS CONFIGURATION.

Operation of Gunn devices in a series d-c arrangement is discussed. Theoretical arguments show that series operation, if attainable, can result in higher-quality microwave output signals and greater efficiency of operation resulting from an increase in r-f output power available from the series device. Three different experimental circuits were employed in the effort to obtain series device operation. The most successful circuit turned out to be a strip-line resonator with a Qo of 7.9 at 1.8 GHz Series Gunn devices operated in this circuit delivered five times more microwave power than single devices operated in the same circuit. Efficiency increased correspondingly, although only a slight improvement in signal quality was noted. The series oscillation seems to be the result of a push-pull type of operation in the strip-line resonator. Push-pull operation should lead to cleaner r-f signals by suppressing even harmonics of the oscillation, but the electric fields necessary to cause series operation are so high that some impact ionization occurs, detracting from the signal quality. Author