Accession Number : AD0803772

Title :   INVESTIGATION OF NEW CONCEPTS AND LINEAR BEAM TECHNIQUES FOR MICROWAVE GENERATION.

Descriptive Note : Quarterly progress rept. no. 3, 1 Apr-30 Jun 66,

Corporate Author : CORNELL UNIV ITHACA NY SCHOOL OF ELECTRICAL ENGINEERING

Personal Author(s) : Dalman, G. C. ; Eastman, L. ; Mackenzie, L. A.

Report Date : OCT 1966

Pagination or Media Count : 124

Abstract : Experiments on a laser triggered transmission cavity have shown that good switching action can occur at high levels of X-band power. A beam plasma test vehicle was developed for the final phase of this task. GaAs Gunn diode ohmic contacts using an eutectic mixture of gemanium and gold were developed. Tin-nickel layered ohmic contacts showed greatly improved operating lifetime. Gunn diodes were operated as oscillators at approximately twice the threshold bias for domain transit operation, with peak powers of 30 watts at X-band. Preliminary tests show domain transit time oscillations can be changed in amplitude, frequency, and wave shape when relative amplitudes of the dc pulses applied to the two segments of a split electrode are varied. Gunn diodes in resonant circuits and biased just below threshold for domain transit time oscillations were strongly driven by microwave signals. A gallium arsenide avalanche p-n junction diode was successfully fabricated using an epitaxially-grown p(+)-n-n(+) wafer purchased. Preliminary data for pulsed operation yields 33 mw and 1/2 % efficiency at 7.5 GHz. The high velocity of electrons in InSb suggests an excellent material for the construction of avalanche transit-time diodes for operation at high microwave frequencies. The study of the anode and cathode initiated vacuum breakdown show that as metal whiskers form on the cathode surface, the cathode initiated breakdown predominates for close electrode spacings while the anode initiated breakdown predominates for large spacings. (Author)

Descriptors :   (*ELECTRONIC SWITCHES, X BAND), (*SEMICONDUCTOR DIODES, MICROWAVE EQUIPMENT), (*KLYSTRONS, EXTREMELY HIGH FREQUENCY), (*PHOTOELECTRIC EFFECT, MICROWAVE EQUIPMENT), (*MICROWAVE EQUIPMENT, SCIENTIFIC RESEARCH), LASERS, ELECTRON BEAMS, PLASMAS(PHYSICS), GALLIUM ALLOYS, ARSENIC ALLOYS, INDIUM ALLOYS, ANTIMONY ALLOYS, SEMICONDUCTORS, MICROWAVES, OSCILLATION, ELECTROSTRICTION, ELECTRON OPTICS, MICROWAVE OSCILLATORS, MICROWAVE AMPLIFIERS, MANUFACTURING.

Subject Categories : Electrical and Electronic Equipment
      Plasma Physics and Magnetohydrodynamics
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE