Low cost crossed-field amplifier

This work is directed toward the achievement of a lower cost slow-wave structure for an injected-beam crossed-field amplifier (IBCFA) than has heretofore been possible. For cost reduction, the meander type of structure is to be supported on an ECOM designed shaped-dielectric substrate instead of individual insulator bars. The slow-wave structure designed and built simulates the configuration of the shaped substrate, but is built using conventional technology. In other respects, the design of the tube is similar to a production line IBCFA. Performance of the first experimental model is considered, in general, representative of the capability of this design. Power output of more than 3 kW and over 30 percent efficiency was achieved in the middle of the 2-4 GHz band, measured with 20 dB gain. Performance in the lower half of the band degraded slowly as frequency was reduced below 2.6 GHz, and degraded more rapidly as frequency was increased above 3.4 GHz. A CFA built with a simulated flat-substrate meander line produced somewhat less power output and efficiency, and less bandwidth, both total (with sole tuning) and instantaneous. Power output up to 2.6 kW with normal RF drive and beam power (as above) was achieved, with operation from 2 to 3.6 GHz. Design corrections for improved performance are foreseen.