Antenna Designs for NFC Devices

Near-field communication (NFC) enables the exchange of information between close devices. The antenna is the indispensable element to transform an electronic device into an NFC system. For both theory and practice, this book presents in detail the design technologies of different antennas. They must meet the NFC ISO 18 092 and 21 481 standards as well as specifications by the NFC Forum for industrial applications, by EMVCo for banking applications and payments, and by CEN for public transport. In a particularly pedagogic way, Antenna Designs for NFC Devices enables designers of communicating object systems and the Internet of Things (IoT) to have access to the mysteries of the design of NFC antennas.

Acknowledgments xi Preface xiii Introduction xvii Part 1. Context 1 Introduction to Part 1 3 Chapter 1. Recap of the Constraints Governing the Design of Antennas for an NFC Device 5 1.1. Normative constraints 6 1.1.1. Uplink from initiator to targets 7 1.1.2. Downlink from targets to initiator 8 1.1.3. “Contactless” standards versus NFC device antennas 10 1.1.4. Technologies 12 1.1.5. “NFC Forum Devices” and “NFC Forum Tags” 12 1.1.6. Modes of communication of an NFC Forum Device 14 1.1.7. Role of an NFC Forum Device 16 1.1.8. Beware of false advertising 17 1.2. Regulatory constraints 17 1.2.1. RF regulations 17 1.3. Constraints on the NFC market 18 1.4. Typological constraints of NFC 19 1.4.1. Application consequences and their direct constraints 20 1.5. Applicational constraints on antenna design 21 Chapter 2. Introduction to and Recap of the Principles Employed in NFC 23 2.1. The physical fundaments of “contactless” and NFC 23 2.1.1. Phenomenon of propagation and radiation 23 2.1.2. Classification of fields and spatial regions 24 2.1.3. Spatial regions 24 2.1.4. Far field: r >> λ/2π (Fraunhofer zone) 24 2.1.5. Intermediary field: r approximately equal to λ (Fresnel zone) 25 2.1.6. Near field: r