DEVELOPMENT OF TPOMI-TYPE 10 MW L-BAND FORWARD-WAVE AMPLIFIER.
RAYTHEON CO BURLINGTON MASS
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The TPOMI amplifier offers the advantages of 40 to 50 efficiency, a broad bandwidth of about 20 over which amplification is obtained, and a compact configuration when compared to linear beam tubes. The main problem areas upon which the investigations were conducted were those of establishing the optimum delay line and sole designs, reduction of sparking or breakdowns, improvement of signal-to-noise ratio, and diminishing the radiation of rf energy in an undesired rapid mode. A close interrelationship was found between the breakdown boundary, radiation, and the signal-to-noise characteristics. Better remedies for breakdown in future tubes would make possible better signal-to-noise ratios as well as higher power levels. The required 10 megawatt peak power level was attained in the QK751 with a gain of 14 to 16 db, a typical efficiency of 40 to 50, and a bandwidth capability of 1220 to 1380 Mc. The full required average power level of 12 kilowatts was obtained successfully, but the specified peak power level could be reached only at pulse durations less than 3 microseconds. Breakdowns limited the output power to about 7 megawatts at the required 10 microseconds pulse duration.