Mode control apparatus for a separable-insert coaxial magnetron

Claim 1

Magnetron apparatus comprising: a vacuum-sealed interaction cavity assembly including: an axially-disposed cathode member, a anode member having an axially-extending medially slotted wall portion radially-spaced from the cathode member, a dielectric window member spaced radially from and surrounding said anode wall portion, and a cavity-sealing metallic connector strip member extending between each axial end portion of the dielectric window member and the proximate axial end portion of the anode wall portion, said dielectric window member sealably covering each anode member slot and having an axial length considerably less than said anode member whereupon the requisite axial extent of at least one of the metallic strip members is of sufficient electrical length of substantially impede longitudinally flowing electrical current, and a resonant cavity assembly formed for removably receiving said interaction cavity assembly, said resonant cavity assembly including: axially-spaced end walls defining the axial extent of the cavity, one of the end walls being adjustable for tuning purposes and the other being relatively fixed whereby the cavity has an adjustable tuning end and a fixed end, said fixed end further having an axially-extending side wall spaced radially from said anode wall portion for providing an axially-extending choke cavity having an entrance opening from said resonant cavity, and said magnetron apparatus further including: a lossy-material choke absorber member in said choke cavity for receiving and suppressing resonant cavity current modes coupled into the choke cavity through said entrance, said one metallic connector strip member extending axially through said choke cavity whereby said cavity-coupled current modes tend to flow longitudinally through it, and an electrically-conductive flexible gasket member disposed in close proximity to said choke cavity entrance between and in electrical contact with said connector strip and said anode wall portion whereby said modes present in said resonant cavity and applied to said strip member at said choke cavity entrance are shorted through said gasket member, said shorting removing said strip member impedance and permitting the desired mode suppression by said choke cavity and its absorber member.