Cathode support structure for magnetron

A cathode structure for a magnetron comprising:

• a ceramic stem including:
• first and second end surfaces,
• a first holding hole extending through said first end surface generally at a center of said first end surface,
• a counterbore formed in said first end surface in surrounding relationship to said first holding hole such that said first holding hole extends into said stem farther than said counterbore,
• a second holding hole extending through said first end surface at a location offset from said first holding hole,
• an annular groove formed in said first end surface and surrounding said first and second holding holes, and
• first and second through-holes each extending through said stem from said first end surface to said second end surface, said first and second through-holes disposed to the outside of said first and second holding holes;
• a first cathode support rod including first and second ends
• a second cathode support rod including first and second ends;
• a first end cap affixed to said second end of said first cathode support rod and disposed in facing relationship to said first end surface;
• a second end cap affixed to said second end of said second cathode support rod and situated closer to said first end surface than said first end cap, said second end cap including a recess through which said first cathode support rod passes;
• a filament cathode extending between said first and second end caps and having said first cathode support rod passing therethrough;
• first and second connecting leads extending through said first and second through-holes, respectively, from said first end surface to said second end surface;
• a first conductive plate electrically interconnecting said first cathode support rod with said first connecting lead;
• a second conductive plate fixed to said first end surface and interconnecting said second cathode support rod and said second connecting lead;
• wherein the first end of said first cathode support rod is located within said first holding hole in spaced relationship to said first and second end surfaces, said second end of said first cathode support rod is spaced from said first end surface, said first cathode support rod extending linearly from its first end to its second end, said first cathode support rod passes through said second end cap and said filament cathode without contacting them;
• said first end of said second cathode support rod being located within said second holding hole in spaced relationship to said first and second end surfaces, said second end of said second cathode support rod being spaced from said first end surface, said second cathode support rod extending linearly from its first end to its second end;
• said first conductive plate having a first portion fixed to said first end surface, and a second portion spaced from said first end surface in a direction toward said end caps and connected to and supporting said first cathode support rod, said first conductive plate is fixed to said first end surface between said counterbore and said annular groove;
• and
• said second conductive plate is fixed to said first end surface between said counterbore and said annular groove and is in non-contacting relationship with said first conductive plate.