The application of reactive metal seals to the design of a high performance metal-ceramic R.F. amplifier tube

Abstract

The new techniques and applications of materials as described by J. E. Beggs in a preceding paper enable a high performance metal-ceramic tube to be designed with structural simplicity and ease of assembly. The utilization of these methods poses new tube design problems, not only those of an electrical nature but also mechanical configuration, parts fabrication, assembly, and processing techniques. A coplanar triode has been developed for grounded-grid r.f. amplifier service in the UHF TV band. It is constructed of alternate rings of ceramic and metal, sealed together through the use of a simple type of butt-seal. This construction is not only mechanically rugged, but the small size and the mechanical configuration provides low inductance connections between the active tube elements and the circuit proper. Although providing these obvious electrical advantages, the small size intensifies the problems of parts tolerances, assembly techniques, and thermal isolation. A discussion of these problems as resolved during the development of the 6BY4 is presented. The use of Beggs reactive metal seals is shown and the operating characteristics of the tube are reviewed.