Patent ID: 8128783

Claim:
A plasma generation device, comprising: a waveguide for propagating a microwave there through, the waveguide including a first waveguide portion and a second waveguide portion downstream from the first waveguide portion; a plurality of plasma generation nozzles secured along a first longitudinal length of the second waveguide portion and operative to receive processing gas and excite the processing gas into plasma using the microwave; and a plurality of stubs secured to the waveguide, the plurality of stubs including: a plurality of first stubs secured to the first waveguide portion and making an impedance match between the waveguide and the plurality of nozzles; a plurality of second stubs secured to the second waveguide portion along a longitudinal length overlapping said first length, wherein one or more of the second stubs are disposed above and around a corresponding one of the nozzles and operative to control an amount of microwave taken by the corresponding nozzle.