A folded-waveguide slow-wave structure equipped with an internal load, includes a central plate comprising a rectilinear beam tunnel of same direction as the longitudinal axis of the central plate, and a serpentine-shaped folded slit having its folds in the direction of the width of the waveguide; a lower plate and an upper plate closing the waveguide, the plates being placed on and under the central plate, respectively; at least one groove of cross section that may be variable, produced along the longitudinal axis of the waveguide, in at least one face internal to the waveguide of the lower plate, the upper plate or the central plate, and at least partially comprising a lossy material; in order to form a closed slow-wave structure through which propagates a hybrid slow wave the amplitude of which is attenuated by at least 20 dB between the start and the end of the portion of the one or more grooves containing a lossy material.

A self-assembling element fabricated using integrated circuit techniques may provide a small diameter helical conductor surrounding an electron beam for the construction of a vacuum electronic device such as a traveling-wave tube for terahertz scale signal.

An electron gun includes: a cathode, which has a cathode holder and a cathode body; and a Wehnelt cylinder. The cathode holder receives the cathode body and the Wehnelt cylinder is suitable for bundling free electrons, which can escape from the cathode body toward the Wehnelt cylinder, to form an electron beam. The Wehnelt cylinder is interlockingly arranged, at least in some parts along a first inner surface facing the cathode holder, on an outer surface of the cathode holder and at least partly extends around the cathode holder.

A folded-waveguide slow-wave structure equipped with an internal load, includes a central plate comprising a rectilinear beam tunnel of same direction as the longitudinal axis of the central plate, and a serpentine-shaped folded slit having its folds in the direction of the width of the waveguide; a lower plate and an upper plate closing the waveguide, the plates being placed on and under the central plate, respectively; at least one groove of cross section that may be variable, produced along the longitudinal axis of the waveguide, in at least one face internal to the waveguide of the lower plate, the upper plate or the central plate, and at least partially comprising a lossy material; in order to form a closed slow-wave structure through which propagates a hybrid slow wave the amplitude of which is attenuated by at least 20 dB between the start and the end of the portion of the one or more grooves containing a lossy material.

A slow-wave circuit comprises: a waveguide comprising a meander-shaped part that transmits an electromagnetic wave and alternately repeats a first folded part and a second folded part folded onto the opposite side to the first folded part; and a beam hole that transmits an electron beam, extends in a predetermined direction, and penetrates the meander-shaped part, wherein the beam hole penetrates the meander-shaped part so that a part of the beam hole protrudes from the first folded part.

A slow-wave structure, a traveling wave tube, an electronic device, and a communication system are provided. The slow-wave structure includes a folded waveguide structure, where the waveguide structure has a cycle in a longitudinal direction and an amplitude in a transverse direction perpendicular to the longitudinal direction, and at least one of an amplitude of a first part of the waveguide structure and a cycle of the first part gradually changes in the longitudinal direction. Therefore, reflection of the slow-wave structure can be reduced, backward wave oscillation can be effectively suppressed, and a wider operating bandwidth can be obtained.

A slow-wave structure, a traveling wave tube, an electronic device, and a communication system are provided. The slow-wave structure includes a folded waveguide structure, where the waveguide structure has a cycle in a longitudinal direction and an amplitude in a transverse direction perpendicular to the longitudinal direction, and at least one of an amplitude of a first part of the waveguide structure and a cycle of the first part gradually changes in the longitudinal direction. Therefore, reflection of the slow-wave structure can be reduced, backward wave oscillation can be effectively suppressed, and a wider operating bandwidth can be obtained.

A slow-wave structure, a traveling-wave tube, and a communication apparatus are provided. The slow-wave structure includes a tube housing, a slow-wave line, and a plurality of support portions. The slow-wave line and the plurality of support portions are all located inside the tube housing, and the tube housing, the slow-wave line, and the plurality of support portions are integrally connected. The plurality of support portions are sequentially spaced apart along the slow-wave line. One end of each support portion is connected to the tube housing, and the other end is connected to the slow-wave line.

A slow-wave structure, a traveling-wave tube, and a communication apparatus are provided. The slow-wave structure includes a tube housing, a slow-wave line, and a plurality of support portions. The slow-wave line and the plurality of support portions are all located inside the tube housing, and the tube housing, the slow-wave line, and the plurality of support portions are integrally connected. The plurality of support portions are sequentially spaced apart along the slow-wave line. One end of each support portion is connected to the tube housing, and the other end is connected to the slow-wave line.