Abstract: A lamp assembly comprising one or more lamp clusters. Each lamp cluster comprises one or more electrodeless UV lamps which are excited by microwaves emitted from a microwave generator. The microwave generator and power supply are enclosed within a housing that is integral with the lamp clusters. The lamp clusters are wholly surrounded by a waveguide. The waveguide, comprising a flange and a distal end cap connected by a mesh, forms an enclosure. The waveguide is essentially UV transparent to allow UV light to pass through but effectively opaque to microwaves in order to substantially contain the microwaves within the waveguide enclosure.