The fundamentals of electromagnetism are simple. Moving electric charges set up electric and magnetic fields. In turn, these fields make the charges move. This dance between charges and fields is described by the Maxwell equations. This brief chapter describes how this comes about. It is, in a sense, everything you need to know about electromagnetism, enshrined in these simple equations. The rest of the book is mere commentary.

To understand what the Maxwell equations are telling us, it’s useful to dissect them piece by piece. The simplest piece comes from looking at stationary electric charges and how they give rise to electric fields. A consequence of this is the Coulomb force law between charges. This, and much more, will be described in this chapter.

The full beauty of Maxwell equations only becomes apparent when we realise that they are consistent with Einstein’s theory of special relativity. The purpose of this chapter is to make this relationship manifest. We rewrite the Maxwell equations in relativistic notation, where the four vector calculus equations are condensed into one, simple tensor equation. Viewed through the lens of relativity and gauge theory, the Maxwell equations are forced upon us: the world can’t be any other way.

The real fun of the Maxwell equations comes when we understand the link between electricity and magnetism. A changing magnetic flux can induce currents to flow. This is Faraday’s law of induction. We start this chapter by understanding this link and end this chapter with one of the great unifying discoveries of physics: that the interplay between electric and magnetic fields is what gives rise to light.

In this chapter, we explore how electric and magnetic fields behave inside materials. The physics can be remarkably complicated and messy but the end result are described by a few, very minor, changes to the Maxwell equations. This allows us to understand various properties of materials, such as conductors.

Chapter 5 discusses the implementation of ISO 18000-63 downlink and uplink communication chains and offers practical code developed in MATLAB for evaluating the signal processing of the full RFID communication chain. The code provided is suitable for custom projects.

Chapter 4 presents a review of the ISO 18000-63 protocol, including data encoding and modulation, and aspects of the transponder memory structure, security, and privacy, and presents real examples of reader–transponder transactions.

Chapter 8 presents a comprehensive discussion of self-jamming in passive-backscatter systems by covering various self-jamming suppression approaches, including some used in commercial integrated circuit RFID reader devices.

Chapter 7 reports on an SDR-based RFID reader design including hardware and software implementations and demonstrates ISO 18000-63-compliant operation in conventional continuous-wave mode and in a novel multicarrier mode.