At the “Laboratorio Nazionale del Sud” two different ion sources are under development: SERSE (a superconducting electron cyclotron resonance ion source to be coupled to the superconducting cyclotron) and MIDAS (a microwave discharge ion source for recoils ionization). In most cases, for these kinds of sources, the coupling system remains empirical, and the exact description of the waves absorbed from the plasma is poorly known. In the following paper an analysis of power transfer characteristics between an arbitrary power source and load impedances is presented. Particular attention is paid to the matching systems. Herein is presented a 2.45 Ghz microwave line for the MIDAS ion source and a proposal for a matching system that can be used in SERSE when it will be driven by three frequencies: 10, 14, and 18 Ghz. ©1998 American Institute of Physics.