Electromagnetic Modeling of RFID-Modulated Scattering Mechanism. Application to Tag Performance Evaluation

Radio-frequency identification (RFID) technology relies on the modulated scattering technique (MST) as a means to convey the information from the tag to the reader. The interaction mechanism between the reader and the tag is described in a physically meaningful way by the reciprocity theorem which is deeply rooted into Maxwell equations. This approach provides a simple and yet complete formulation that allows to fully describe the interaction between the reader and the tag, even in complex environments. From this formulation, a clear understanding is derived on how the different design tradeoffs affect system performance. Based on this approach, the paper is focused on several issues of practical relevance for antenna tag design such as maximum power transfer, maximum sensitivity, and nonlinearity effects.