[en] Our first aim was to optimize the power fraction absorbed by minority ions. This led to the concept of optimized antenna which is adapted to transfer power from the source to the particle (minority ions) sink. Such an antenna can be closely approximated by a quadrupole antenna. But due to the coupling between the species, and the nature of the power transfer to particles, ions and electrons, the more complete condition of equating the power delivered by the antenna to the absorption by minority ions and by electrons was discussed. And, in this case, monopole and quadrupole antenna structure was equally attractive