Patent ID: 6593695
Filing Date: 2003-07-15
Classification: H01J

Abstract:
A microwave electron tube, comprising:an electron gun for emitting an electron beam having a predetermined voltage; a collector spaced from said electron gun, said collector collecting electrons of said electron beam emitted from said electron gun; an interaction structure defining an electromagnetic path along which an applied electromagnetic signal interacts with said electron beam, said interaction structure further comprising a plurality of cavity walls and a plurality of permanent magnets, said cavity walls each having an aligned opening providing an electron beam tunnel extending between said electron gun and said collector, said electron beam tunnel defining an electron beam path for said electron beam, said magnets providing a magnetic flux path to said electron beam tunnel, said electromagnetic signal having a first passband and a second passband, said first passband having a upper bandedge, said second passband having a first, second and third space harmonics and a lower bandedge; wherein, said interaction structure further includes respective cavities defined therein interconnected to provide a coupled cavity circuit, said cavity walls separating adjacent ones of said cavities, said cavity walls each further having an iris for coupling said electromagnetic signal therethrough;wherein, said iris and said cavity walls are dimensioned to allow said interaction structure to exhibit an inverted slot mode, said inverted slot mode comprising a cavity resonant frequency that is substantially larger than a corresponding iris cutoff frequency and wherein said cavity resonant frequency is associated with said lower bandedge of said second passband, and said iris cutoff frequency is associated with said upper bandedge of said first passband; andwherein, said predetermined voltage of said electron beam is selected to allow said electron beam to interact with said third space harmonic of said second passband.