ELECTRON DEVICES FOR MICROWAVE GENERATION.
Final rept. 1 Mar 63-31 Dec 67,
NORWEGIAN DEFENCE RESEARCH ESTABLISHMENT KJELLER
Pagination or Media Count:
Investigations of oscillations in Cuccia-couplers and pumpless amplification of the fast cyclotron wave are reported. Several amplifying tubes with identical input and output Cuccia-couplers, separated only by a drift region, have been built. Gains were typically 30 db but efficiencies only about one per cent. An oscillator based upon this mechanism was built in the 600 MHz frequency range. Theoretical estimates on the transient behaviour of Gunn domains indicate transients unimportant for frequencies exceeding X-band. Simple models are used for calculations of efficiency, output power and RF-resistance in the domain and LSA modes. Efficiencies are around 25 when a third harmonic voltage is permitted across the sample. In the growing space charge mode RF-resistances may be negative even with average fields below the Gunn threshold. Schottky barrier measurements of donor concentration are found essential for characterization of epitaxial GaAs layers. A pulsed cavity controlled oscillator around 500 MHz has given 27 W peak power with 10 efficiency. Author
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- Solid State Physics