Extended interaction device comprising a core and shell device body for supporting ring-shaped resonant cavities, electron beam tunnels and a coupling groove therein and an output waveguide at a middle portion of the shell

A millimeter-wave extended interaction device, comprising:

• a device body comprising a shell and a core;
• the core comprising resonant cavities, a coupling groove, and electron beam tunnels;
• and the shell comprising a coupling hole;
• and
• an output waveguide;
• wherein:
• the shell and the core are in a cylindrical shape, and are coaxially disposed around a longitudinal axis;
• the core is disposed within the shell;
• the coupling groove is in a cylindrical shape, and is recessed inward from an outer surface of the core;
• the resonant cavities are a set of ring-shaped cavities with a radial height of 2/5λ, to 3/5λ, are coaxially disposed around the longitudinal axis, and are parallel to each other and equally spaced from each other;
• wherein λ, represents an operating wavelength;
• the resonant cavities are connected to the coupling groove;
• the electron beam tunnels are arranged at equal radian intervals and parallel to the longitudinal axis, and each electron beam tunnel is connected to the resonant cavities and extends between two end walls of the core;
• the coupling hole extends outward from an inner surface of the shell;
• the coupling hole is connected to the coupling groove;
• the output waveguide is disposed at a middle portion of the shell between two ends of the shell, and is connected to the coupling hole;
• the resonant cavities are coupled to the output waveguide via the coupling groove and the coupling hole;
• and
• the core and the shell are sealed and fixed to each other, and the output waveguide and the shell are sealed and fixed to each other.