A millimeter-wave extended interaction device, including: a device body; resonant cavities; electron beam tunnels; an output waveguide; and a coupling hole. The device body includes a shell and a core, and an annular coupling channel is disposed between the shell and the core. The resonant cavities are a set of ring-shaped cavities with a radial height of 2 /5 , to 3/5 , parallel and equally spaced around an axis of the core. The electron beam tunnels are arranged at equal radian intervals and parallel to the axis of the core. The output waveguide is disposed in the middle of the shell and communicates with the annular coupling channel through a coupling hole. The core and the inner surface of the shell are sealed and fixed, and the output waveguide and the shell are sealed and fixed.

A magnetron characterized by a supporting cylinder, a field emission cathode, a slow wave structure, and a waveguide. The slow wave structure includes an anode block positioned coaxial with and surrounded by the field emission cathode. The anode block includes sixteen radially-projecting vane panels defining sixteen resonant cavities therebetween. Each of the resonant cavities may comprise a resonant channel portion positioned radially proximate to and axially coextensive with a center axis of the anode block. A void between the anode block and the field emission cathode, along with the resonant cavities, define an interaction region. The waveguide, comprising a cylinder characterized by an exterior layer surrounding an interior void, is capacitively coupled to the slow wave structure and configured to deliver radio frequency (RF) energy extracted from the interaction region by one (or, optionally, two) excitation rings mounted at a downstream end of the anode block.

A high power RF energy device component is disclosed that is exposed to high power RF energy in a vacuum environment, and includes a multipactor-inhibiting carbon nanofilm covering at least one surface of the component. A secondary electron efficiency emission (SEE) coefficient of the multipactor inhibiting carbon nanofilm is desirably less than a SEE coefficient of the underlying surface of the component.

A high power RF energy device component is disclosed that is exposed to high power RF energy in a vacuum environment, and includes a multipactor-inhibiting carbon nanofilm covering at least one surface of the component. A secondary electron efficiency emission (SEE) coefficient of the multipactor inhibiting carbon nanofilm is desirably less than a SEE coefficient of the underlying surface of the component.

Provided are a magnetron and a microwave heating device. The magnetron includes a tube core, a first tube shell, a second tube shell, an output ceramic, an antenna cap, and an antenna. The first tube shell, the tube core, the second tube shell, the output ceramic, and the antenna cap are connected in sequence. The antenna extends into the tube core, and sequentially passes through the second tube shell and the output ceramic and extends into the antenna cap. A height H1 of the second tube shell relative to the tube core is smaller than or equal to 14 mm, and a ratio H1/S of a height H1 of the tube core to a cross-sectional area S of the antenna ranges from 0.4 to 3.3.