Method and apparatus for interaction with a modulated off-axis electron beam
AssigneeL-3 Communications Corporation
InventorsRichard Donald Kowalczyk, Mark Frederick Kirshner, Craig Bisset Wilsen, Chad Daniel Marchewka
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Abstract
An output circuit for a microwave tube is provided that has generally high interaction impedance for good efficiency, has high average power capability, and is physically large for a given operating frequency. The output circuit is designed to operate in conjunction with an off-axis, bunched electron beam. Electromagnetic fields are applied to the region in which the electron beam propagates to impart an azimuthal velocity to the bunched electron beam. The electron bunches then interact synchronously with a resonant output structure to excite radio-frequency modes from which energy can be extracted and applied to a load.
Claims30
An output circuit for an electron beam device comprising:
- a cavity substantially cylindrical in shape comprising at least an outer wall and a central axis of symmetry;
- an electron gun adapted to produce an electron beam propagating through the cavity wherein:
- the electron beam propagates through the cavity along a path that is offset from the central axis of symmetry;
- the electron beam propagates with a velocity that has a component along a direction parallel to the central axis of symmetry;
- and
- the electron beam is spatially bunched into a plurality of electron bunches;
- a substantially annular output structure situated within the cavity and centered on the central axis of symmetry;
- and
- at least one electromagnetic generating structure adapted to induce electromagnetic fields within the cavity to impart an azimuthal velocity to the electron beam;
- wherein the output structure is adapted to interact synchronously with the plurality of electron bunches to cause at least one radio-frequency mode of the output structure to be excited.
An output circuit for an electron beam device comprising:
- a cavity substantially cylindrical in shape comprising at least an outer wall and a central axis of symmetry;
- an electron gun adapted to produce an electron beam propagating through the cavity wherein:
- the electron beam propagates through the cavity along a path that is offset from the central axis of symmetry;
- the electron beam propagates with a velocity that has a component along a direction parallel to the central axis of symmetry;
- and
- the electron beam is spatially bunched into a plurality of electron bunches;
- a substantially annular output structure situated within the cavity and centered on the central axis of symmetry, wherein the output structure is adapted to include a plurality of slots for developing a slow-wave structure;
- and
- at least one electromagnetic generating structure adapted to induce electromagnetic fields within the cavity to impart an azimuthal velocity to the electron beam;
- wherein the output structure is adapted to interact synchronously with the plurality of electron bunches via the slow-wave structure developed in the output structure to cause at least one radio-frequency mode of the output structure to be excited.
In a system comprising an electron gun adapted to generate an electron beam, a substantially cylindrical cavity comprising a central axis of symmetry, and a substantially annular output structure, a method of exciting a radio-frequency mode in the output structure comprises:
- propagating the electron beam through the cavity along a path that is offset from the central axis of symmetry;
- spatially bunching the electron beam into a plurality of electron bunches;
- applying a magnetic field along a direction parallel to the central axis of symmetry of the cavity;
- applying an electric field along a direction perpendicular to the central axis of symmetry of the cavity and along a radius of the cavity;
- imparting an azimuthal drift velocity to the plurality of electron bunches under the influence of the perpendicular electric and magnetic fields;
- and
- exciting at least one radio-frequency mode of the output structure as the plurality of electron bunches interact synchronously with the output structure.
In a system comprising an electron gun adapted to generate an electron beam, a substantially cylindrical cavity comprising a central axis of symmetry, and a substantially annular output structure, a method for exciting a radio-frequency mode in the output structure comprises:
- propagating the electron beam through the cavity along a path that is offset from the central axis of symmetry;
- spatially bunching the electron beam into a plurality of electron bunches;
- applying a first magnetic field along a direction parallel to the central axis of symmetry of the cavity;
- applying second magnetic field along a direction opposite to the first magnetic field;
- imparting an azimuthal velocity to the plurality of electron bunches under the influence of the first magnetic field and second magnetic field;
- and
- exciting at least one radio-frequency mode of the output structure as the plurality of electron bunches interact synchronously with the output structure.
Dependencies are inferred from the claim text.