Communications & Power Industries, Inc.

Litton Systems, Inc.

Merrald B Shrader

Andrew A Haase

A signal output assembly for an inductive output amplifier comprises a primary output cavity including a drift tube enclosing a modulated electron beam. The density modulated beam passes across a gap separating portions of the drift tube and induces an amplified RF signal into the primary output cavity. A secondary output cavity comprises a coaxial resonator terminated in an inductive coupling loop, and a waveguide having a ridge. The coaxial resonator and the inductive coupling loop have a combined electrical length approximately equivalent to an odd multiple of one-quarter wavelengths of the input signal (n&lgr;/4), where n is an odd integer. The coaxial resonator is electrically connected perpendicularly to a center of the ridge such that first and second portions of the ridge extend in opposite directions from the connection with the coaxial resonator to respective ends of the waveguide. The first and second ridge portions each have a length approximately equivalent to an odd multiple of one-quarter waveguide wavelengths of the input signal (n&lgr;,/4), where n is an odd integer. The inductive coupling loop is coupled at a first end thereof to an end of a center conductor of the coaxial resonator and at a second end thereof to an outer conductor of the coaxial resonator. The inductive coupling loop extends into the primary output cavity and is adapted to couple the amplified RF signal from the primary output cavity to the secondary output cavity. The amplified RF signal is thereafter coupled out of the secondary output cavity through a secondary inductive coupling loop.

Inductive output amplifier output cavity structure

A vacuum tube for handling an r.f. signal having a predetermined frequency range comprises a cathode, a heater, and a non-electron emissive grid. The grid is positioned from the cathode by the distance an emitted electron from the cathode can travel in a quarter cycle of the r.f. signal. Outer and inner metal tubes forming a resonant line of a signal coupler are respectively connected to the grid and cathode. R.F. absorbers absorb r.f. fields in an interaction region between an anode and the grid. In one embodiment a coupling loop is between metal tubes at an end of the tubes spaced n.lambda./4 from the grid and cathode. In a second embodiment the coupler includes a coaxial line having an inner conductor connected to a first metal face, spaced from a second opposed metal face by a solid dielectric. An outer conductor is connected to a third metal face, spaced from a fourth opposed metal face by the dielectric. The third and fourth faces surround the first and second faces. The first and third faces are at ground potential while the second and fourth faces are at high negative DC voltages. The second and fourth faces are respectively at common ends of interior and exterior coaxial metal tubes forming a .lambda./2 coupler. Hollow inductive structures extend between the inner and outer metal tubes and at different locations along the tubes. Bias leads may be inserted into the inductive structures for shielding.

High frequency vacuum tube with closely spaced cathode and non-emissive

A vacuum tube for handling an r.f. signal having a predetermined frequency range comprises a linear electron beam emitting cathode, a heater and a non-electron emissive current modulating grid. The grid is positioned from the cathode by the distance an emitted electron from the cathode can travel in a quarter cycle of the r.f. signal. Outer and inner coaxial metal tubes forming a resonant line of a signal coupler are respectively connected to the grid and cathode so electrons passing through the grid are in bundles in an interaction region between an accelerating anode and the grid. Ferrite tiles absorb r.f. fields in the interaction region. In one embodiment a signal coupling loop is between metal tubes at an end of the tubes spaced 3.lambda./4 from the grid and cathode. In a second embodiment the coupler includes a low voltage coaxial line having an inner conductor connected to a first metal face, spaced from a second opposed metal face by a solid dielectric. The coaxial outer conductor is connected to a third metal face, spaced from a fourth opposed metal face by the solid dielectric. The third and fourth faces surround the first and second faces. The first and third faces are at DC ground potential while the second and fourth faces are at high negative DC voltages. The second and fourth faces are respectively at common ends of interior and exterior coaxial metal tubes forming a .lambda./2 coupler. Other ends of the tubes are connected to the cathode and grid. Bias leads for the grid and cathode are connected to the exterior and interior tubes at positions .lambda./4 from the grid and cathode, while a heater lead goes through the interior tube at a position .lambda./4 from the grid and cathode.

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Buena Vista, CO, United States of America

Merrald B Shrader