Abstract: An electron beam tube is described, having a flat cathode and a flat, close-spaced grid to density modulate the beam. The beam passes through an apertured anode and then through a hollow drift tube which is the central conductor of a coaxial resonator. A gap in the drift tube extracts wave energy from the density modulated beam.The cathode-grid region is electrically isolated from the output resonator by the length of the drift tube which is cut off as a waveguide. The circuit is thus completely grounded-grid. The input resonator, a coaxial line connected across the cathode-grid space, is loaded by the input conductance, so as to reduce the gain. The invention increases the gain by introducing regeneration between the grid-anode space and the cathode-grid space. This is done by a coupled coaxial resonator system.

Abstract: An efficient relatively high-power inductive output linear electron beam tube with broad-band capabilities is disclosed which is density modulated with a grid applying to the beam an RF modulating signal. The grid has a large active area which may be of the order of ten square inches, is closely spaced one-twentieth the grid diameter or less to a thermionic cathode, and is comprised of a plurality of curved thin narrow elongated members. With the aid of an annular anode downstream of the grid, the beam is accelerated by DC potential of at least several kilovolts. A high-isolation input signal means includes adjacent but physically and electrically isolated wide-diameter, axially reduced annular cathode and grid lead means for leading both the DC beam-accelerating potential into the cathode, and the modulating RF signal into the grid with minimal impedance.

Abstract: A grid-controlled electron tube is constructed with a common anode and an array of individual cathode-grid modules. The simple modules can be built with greater accuracy than large, complex electrodes. The modules can be individually tested before final assembly, and can be individually replaced in case of a failure during construction or later operation. In a preferred embodiment, the cathode is a cylindrical filament surrounded by a coaxial grid, each grid turn being mounted to a common support on the side opposite the anode. In a tetrode embodiment, additional focusing bars at the sides of the grid direct electrons into beams which pass between large screen-grid wires.