Investigation of nonresonant couplers for fast cyclotron waves in type-M electron beams

Abstract

The following conclusions can be drawn from the preliminary theoretical and experimental investigations of electronic attenuators and transmission lines formed by cyclotron waves on type-M beams with nonresonant couplers. 1. Distributed type-M couplers can establish quite strong coupling between the beam and the field, with practically complete transmission of the signal power along the beam. The absorption and bandwidt attained can be used as the basis for the design of inertialess controlled attenuators. 2. The investigation of the possibility of making transmission lines with distributed couplers on fast cyclotron waves on a type-M beam shows that the development of such systems is quite feasible, since practically complete signal power transfer from one stage to another can be obtained over a fairly wide frequency range. There do not appear to be any fundamental difficulties in the way of increasing the bandwidth of such devices. 3. For the development of type-M devices it appears to be preferable to use a backward-wave circuit with an inverse system. In this case, the current flows near the retarding system, permiitting high coupling impedances as well as an interaction efficiency which is high compared to that obtained with a forward wave. 4. The use of type-M circuits requires small magnetic gaps, which considerably eases the problem of creating large magnetic fields. This fact may be useful for application of the devices to higher frequencies in the microwave band.