APPARATUS FOR COUPLING MICROWAVE ENERGY TO AN ELECTRODELESS LAMP

摘要

A source of microwave energy (11) is connected to a waveguide (14) having a slot (16) along one wall (17) thereof. A nominally cylindrical cavity (18) enclosing an electrodeless lamp (21) is closed at one end and coupled at a second end to the slot (16). The nominally cylindrical cavity (18) has a non-cylindrical surface portion (26) which increases coupling from the slot (16) to a second resonant mode which is orthogonal to a first primary resonant mode, creating a high amplitude standing wave in the region of the electrodeless lamp. Once ignition of the lamp occurs, the impedance of the lamp decreases significantly, and most of the microwave power for sustaining illumination is coupled to the electrodeless lamp in the first resonant mode producing a substantially matched load to the microwave source (11).