"Version: 20241001"--Title page verso.Includes bibliographical references.1. Introduction -- 1.1. Conventional traveling-wave tubes -- 1.2. Problems encountered2. Planar slow-wave structures -- 2.1. Periodic planar slow-wave structures -- 2.2. Axial periodic slow-wave structures3. Planar electron optical systems -- 3.1. Introduction -- 3.2. Radial planar EOSs -- 3.3. Angular radial planar EOSs …