Abstract: A coil extension of the RF coupling coil, surrounding an electrodeless light bulb containing an inert gas and selected chemical elements, generates a voltage at the distal end thereof which is higher than that which appears across the RF coupling coil proper, and wherein the high voltage from the distal end of the coil extension is returned to the light bulb through a point contact electrode located in relatively close proximity to the low voltage end of the RF coupling coil.

Abstract: A high frequency directional coupler having improved intermodulation distortion performance is disclosed. The coupler includes input, output, reflected, and incident ports, and current and voltage transformers. The current transformer includes at least one primary winding connected between the inlet and outlet ports and at least one secondary winding coupled with the primary winding and connected between the reflected port and ground. The voltage transformer includes a plurality of series-connected primary windings connected between the reflected and incident ports, and a plurality of series-connected secondary windings coupled with said voltage transformer primary windings, respectively, and connected between the input port and ground. Shunt capacitors connected with the input, output, reflected and incident ports increase the bandwidth of the coupler.