Properties of ring-plane slow-wave circuits

Ring-plane circuits consist of circular rings or slotted pipes supported by one or more radial planes. These circuits propagate slow waves
(v_{p} < c)
in one or more modes, with velocity and impedance governed primarily by the ring or slot resonances much as on planar ladders. The multimode behavior depends very much on the mutual coupling near the radial planes. Tests of many variations about a prototype configuration are presented, including methods for suppression of unwanted modes. The results are given in terms of ω -- β diagrams, field shapes and impedances. The study presents essentially all parameters necessary for design of circuits for traveling-wave amplifiers and backward-wave oscillators, as well as information useful in other applications, such as linear accelerators. Ring-plane circuits are of large diameter
(ka \ge 1)
, are quite fast
(v_{p}/c
large) and have relatively large impedances. The radial support planes provide good heat conduction paths, allowing for high average power capability. These properties make these circuits well suited for use in high-power, high-frequency traveling-wave tubes.