A class of deflection-modulated, high-power microwave amplifiers

An unusual deflection-modulated, fast-wave electron device is analyzed. It has several unique properties; the electron beam is unbunched and is perpendicular to the direction of power flow in the circuit, and the circuit could be a simple fundamental-mode rectangular waveguide. The amplifier consists of an electron gun, a deflection cavity, an optional beam-bending system, and an output interaction region. An idealized theory showing that 100% electronic efficiency may be achieved, and several large-signal calculations with over 90% electronic and circuit efficiencies, are presented. The power, gain, and frequency limits to this type of amplifier or frequency multiplier are discussed. The beam power must be greater than 100 kW for efficient operation because the output circuit losses and deflection power depend on beam voltage, not on beam power. The devices operate best at frequencies below a few gigahertz because of limitations on the ratio of beam size to circuit size. The power gains vary between 10 and 25 dB.