In order to extend the length of the coaxial cable connection between an electrodeless fluorescent lamp and the associated electronic ballast, a new structure for electrodeless lamp systems is proposed in this paper. Impedance matching networks in the structure are analyzed and designed based on the transmission characteristics of coaxial cable. Efficient topologies and formulae for the matching networks are put forward. Experimental results for a 2.65 MHz electrodeless lamp system with up to 25 m of coaxial cable which validate the structure are presented.