Patent ID: 7315126

Claim:
An amplifying device, comprising: an electron gun emitting an electron beam; a collector spaced from the electron gun, the collector oriented to collect electrons of the electron beam emitted from the electron gun; and an interaction structure interposed between the electron gun and the collector, defining an electromagnetic path along which an applied electromagnetic signal interacts with the electron beam, the interaction structure further comprising a plurality of polepieces and a plurality of magnets, the polepieces each having an aligned opening to collectively provide an electron beam tunnel having an axis extending between the electron gun and the collector to define an electron beam path for the electron beam, the polepieces providing a magnetic flux path to the electron beam tunnel from the magnets; wherein the interaction structure further includes plural cavities defined therein interconnected to provide a coupled cavity circuit, at least one of the plurality of polepieces separating adjacent ones of the plural cavities and having an iris for coupling the electromagnetic signal therethrough, at least one of the plurality of polepieces further having a void that crosses the electron beam tunnel and is aligned perpendicularly to the beam tunnel axis.