Tapered traveling wave tube
AssigneeAmpWave Tech, LLC
InventorHenry G. Kosmahl
Life of this patent
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Abstract
A structure to eliminate non-fundamental space harmonics in helical traveling wave tubes is disclosed. The helix radius and pitch are simultaneously varied over a short distance to improve the efficiency and performance of the tube. This new geometry, an adverse space harmonics taper (ASHT), renders the fundamental phase velocity invariant to frequency and distance effects, while adversely affecting all other space harmonics. Another aspect of the invention reduces the temperature of the helix and further improves tube efficiency, so that electronic efficiencies approach 30% in a linear performance region.
Claims32
A helical traveling wave tube for amplifying an RF signal, comprising:
- a cathode, placed at a near end of the tube;
- an anode near the cathode, and operably connected to induce a beam of electrons to flow between the anode and the cathode;
- a collector, placed at a far end of the tube, and constructed to receive the flow of electrons;
- a helical conductor section between the cathode and the collector, said helical conductor section having an RF input, an input section, a middle section, an output section, and an RF output;
- and
- at least one magnet surrounding the helical section, operative to focus the beam of electrons,
- wherein the input section of the helical conductor is tapered, by simultaneously varying a pitch and a radius of the helical conductor, such that the velocity of a fundamental RF signal along the helical conductor remains substantially synchronous with the velocity of the electron beam.
A helical conductor for use in a traveling wave tube, comprising:
- a middle section;
- an input section connected to a near end of the middle section;
- and
- an output section connected to a far end of the middle section, wherein the input section is tapered by simultaneously varying a pitch and a radius of the helical conductor.
A helical traveling wave tube for amplifying an RF signal by means of a beam of electrons, comprising:
- a helical conductor, said helical conductor having an RF input, an input section, a middle section, an output section, and an RF output;
- at least one magnet surrounding the helical conductor, operative to focus the beam of electrons;
- a housing encompassing at least the helical conductor;
- and
- a support structure between the housing and the helical conductor,
- wherein the input section of the helical conductor is tapered, by simultaneously varying a pitch and a radius of the helical conductor, such that the velocity of a fundamental RF signal along the helical conductor remains substantially synchronous with the velocity of the electron beam.
Dependencies are inferred from the claim text.