The gain and bandwidth characteristics of backward-wave amplifiers

The problem of designing backward-wave amplifiers to yield specified pass band characteristics is discussed. Detailed universal curves of gain and bandwidth for both single-circuit and cascade amplifiers are presented. Simple charts are developed which facilitate the design procedure. Experimental results are correlated with the theory and indicate its usefulness. The skirt-selectivity of cascade amplifiers is discussed. A specific design example is given to demonstrate the design method and to indicate the range of bandwidths obtainable from helix-type amplifiers.