Applicator for microwave enhanced chemistry

Abstract

According to the present invention, a microwave generator includes a variable voltage provided from a first transformer to a second transformer having a secondary winding split into a filament winding cathode low AC signal and a secondary winding providing a high voltage which is doubled and rectified in a half-wave voltage doubler for providing a pulsed DC signal through a ballast resistor to a magnetron anode responsive to an electromagnetic field. In still further accord with the present invention, a microwave sample cavity includes a waveguide, and a hole for receiving a sample to be microwave-heated, and an inductive tuning post all on a straight line, wherein the hole is adjacent the waveguide and the post is distant from the waveguide

1 . A microwave applicator, comprising: a circular disc-shaped waveguide, having a top and a bottom, said circular waveguide being responsive to microwave signals from a microwave generator provided to said waveguide at an inlet at the outer edge of said circular waveguide for communicating said microwave signals through said waveguide; an inductive tuning post fixed in said circular waveguide, oriented parallel to the electric field so as to provide additional inductive susceptance in parallel with the waveguide; a depression on the top of said circular waveguide, and between said post and said inlet, said depression for receiving a sample in said depression; 
     
     
         2 . The applicator of  claim 1  wherein said inlet, depression and post all lie on a substantially straight line on a plane parallel with the top and bottom of said circular disc-shaped waveguide. 
     
     
         3 . The applicator of  claim 1 , wherein said inlet, depression and post all lie on a substantially straight line on a plane parallel with the top and bottom of said circular disc-shaped waveguide. and further including a dielectric lens. 
     
     
         4 . The applicator of  claim 1  further including a second inductive tuning screw which is not fixed but may be screwed further into or out of the waveguide, said screw being oriented parallel to the electric field so as to provide additional inductive susceptance in parallel with the waveguide.