Abstract: A section of pipe, for a device for treating a gas by exciting the latter by way of incident microwave radiation suitable for producing a surface-wave plasma in the gas, including a discharge tube made of dielectric material intended to pass through the device in a region for concentrating the incident radiation. The tube comprises, over at least part of its length, a double wall.

Abstract: The invention concerns a device for exciting a gas comprising a hollow structure (24) forming a waveguide to be connected to a microwave generator and means for circulating a gas through the structure. The gas circulating means comprise an assembly of at least two hollow tubes (46, 48) made of dielectric material respectively passing through said structure (24) in the zones wherein the amplitude of the electric field associated with the incident wave is substantially the same.

Abstract: Device for exciting a gas comprising a hollow structure forming a waveguide, made of an electrically conductive material, connected to a microwave generator and including a passage for a hollow dielectric tube adapted for flow of the gas to be excited, the hollow structure further including a wave-concentrating region designed to concentrate microwave radiation produced by the generator onto the tube, during operation of the device, for the purpose of producing a surface wave plasma in the gas, at least one electromagnetic screening sleeve made of a conductive material, fastened to the hollow structure and extending along the extension of the passage so as to surround the hollow tube.