DESIGN OF A HIGH-POWER X-BAND MAGNICON AMPLIFIER

We present a design study for an X-band frequency-doubling magnicon am plifier driven by a 500 keV, 172 A beam from a field-emission diode. T his study makes use of steady state particle simulations employing the realistic fields of magnicon cavities connected by beam tunnels, and includes the effects of finite electron beam diameter. The simulations propagate an electron beam through a sequence of deflection cavities at 5.7 GHz, followed by an output cavity that operates at 11.4 GHz. Th e deflection cavities and the output cavity contain synchronously rota ting TM modes. The deflection cavities progressively spin up the beam transverse momentum, until alpha = upsilon(perpendicular to)/upsilon(z ) > 1, where upsilon(perpendicular to) and upsilon(z) are the velocity components perpendicular and parallel to the axial magnetic field. Th e output cavity uses this synchronously gyrating beam to generate micr owave radiation at twice the drive frequency. Self-consistency of the simulation is achieved by iteration until power balance exists in each cavity, and until the optimum RF phase in each cavity is determined. The final magnicon circuit should produce 20 to 50 MW at 11.4 GHz, dep ending on initial beam diameter, with a drive power of 1 kW at 5.7 GHz .