A 5.7-GHz, 100-kW microwave source based on the monotron concept

A conceptual transit-electron tube based on the monotron effect is described. The device comprises a temperature-limited diode gun operating at 33-kV cathode voltage and 40-A beam current. As indicated by two-and-a-half-dimensional (2.5-D) particle-in-cell simulations, a 5.7-GHz single frequency radiation has been generated at the peak-power output level of 100 kW. The self-induced RF voltage across the diode gap produces a density modulation on the beam electrons which translates into a negative electronic admittance at proper applied dc voltages. Assuming a strictly monoenergetic beam, the transit-time effect-underlying the operation principle of the device-is examined by means of a small-signal analysis from which an analytic expression for the starting current is derived.