Design Factors of the Bell Telephone Laboratories 1553 Triode

In Developing microwave relay systems for frequencies around 4000 megacycles, one of the major problems is to provide an amplifier tube which will meet the requirements on gain, power output, and distortion over very wide bands. As the number of repeaters is increased to extend the relay to greater distances, the requirements on individual amplifiers for the system become increasingly severe. A tube developed for this service is the microwave triode B.T.L. 1553, the physical and electrical characteristics of which were briefly described in a previous article.1In the development of such a tube, both theoretical and experimental factors arc involved; illustration of these factors in some detail is the purpose of the present paper.