ABSTRACT
This chapter aims to provide support to Radio frequency identification device (RFID) system designers in what is probably the least understood aspect of system design, that of the electromagnetic propagation to and from the label. It examines a formal statement of the laws of electrodynamics, and use them to derive boundary conditions that apply where fields interact with materials. The chapter discusses the retarded potential solutions of Maxwell’s equations and their utility in developing near and far radiated fields, especially for infinitesimal electric and magnetic dipoles. It illustrates a number of field creation structures or near and far fields, and label antenna parameters for use in various object geometries. The chapter describes coupling volume theory for electric field- and magnetic field-sensitive antennas at length and the relation to far-field antenna theory. In RFID systems, the coupling can be via the magnetic field or the electric field.
