Sterilisation apparatus for generating hydroxyl radicals

A sterilisation apparatus comprising:

• a microwave source arranged to generate microwave energy;
• a mist generator arranged to generate a flow of water mist;
• a manifold connected to receive the flow of water mist from the mist generator and configured to direct the flow of water mist through an internal volume thereof towards a manifold outlet;
• and
• a power distribution device having an input port coupled to the microwave source and a plurality of output ports coupled to the internal volume of the manifold,
• wherein the power distribution device is configured as a power splitter that operates to distribute microwave energy received at the input port between the plurality of output ports to generate a plasma in a plasma generating region of the internal volume.