Abstract: The invention relates to a triode type cathode structure comprising a cathode assembly composed of a cathode electrode (33), a layer of electron emitting material (34) and a resistive layer (36) inserted between the cathode electrode (33) and the layer of electron emitting material (34) to connect them together electrically, the structure also comprising a grid electrode (35) separated from the said cathode assembly by a layer of electrical insulation (31). The cathode electrode (33) and the layer of electron emitting material (34) are arranged one at the side of the other.

Abstract: Switching apparatus for switching on and off one or more microwave tubes. A preferred embodiment of the switching apparatus comprises a solid state magnetron switcher that switches a plurality of magnetrons on and off using a plurality of high voltage (IGBT) switches. The microwave tubes or magnetrons are driven from a single power supply. The technical approach employed in the present invention places all microwave tubes or magnetrons into low level oscillation prior to switching them into full conduction. This maintains minimal voltage across the high voltage switches while allowing only a small percentage (1-2%) of full load current to be drawn.