Lower and upper bounds of the power absorbed by lossy scatterers located in the near-field region of an antenna

To minimize or maximize the power absorbed in near-field regions remains a complicated problem, for which mostly numerical or experimental particular solutions have been proposed. The method proposed here (Derat et al. (2004)), provides a new answer to this question, by describing the power transfer from a source to a lossy scatterer with an equivalent junction excited by a set of generators. A new matrix formulation of this equivalent junction model is exposed and used to determine lower and upper bounds of dissipated power which is possible to reach with a well-designed source, in the case where both the source and scatterer are surrounded by an homogeneous lossless medium. Those bounds are shown to present a separate dependence on the source and scatterer. Moreover, the only antenna parameters impacting on those limits are the frequency of operation and the total radiated power.