Chapter 11 Radio Frequency Identification and Near Field Communication

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Electrical Engineering

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Oct 30, 2023

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Chapter 11 Radio Frequency Identification and Near Field Communication What is RFID? • Radio frequency identification (RFID) – Technology similar to barcode labels – Uses RF waves instead of laser light to read the product code – Stores product information in electronic tags • That contain an antenna and a chip • EPCglobal Inc. – Establishes RFID standards and services for real-time, automatic identification of information • In the supply chain of any company - EPCglobal Inc. (cont’d) o Adopts the ISO 18000 series of standards for RFID  Including the frequencies and PHY and MAC layer specifications o Concentrates on defining services and higher layer functions of the standards RFID System Components • Components required to implement an RFID system: – Tags – Antennas – Readers – Software – EPCglobal Network services Electronic Produce Code • Electronic Product Code (EPC) – Standardized numbering scheme – Can be programmed in a tag and attached to any physical product – Unique number or code associated with each item • So that it can be identified electronically – EPCs are usually represented in hexadecimal notation – EPC is either 64 or 96 bits long RFID Tags • RFID tags – Commonly known as transponders

• A combination of transmitter and responder – Includes an integrated circuit • Contains some non-volatile memory and a simple microprocessor – Can store data that is transmitted in response to an interrogation from a reader • Device that captures and processes the data received from the tags • Basic types of tags – Passive tags (most common type) • They are small, can be produced in large quantities at low cost, and do not require battery power • Use the electromagnetic energy in the RF waves – Active tags • Equipped with a battery • Can transmit the signal farther away • Have a limited life due to the battery • Beacons transmit on a periodic basis • Basic types of tags (cont’d) – Semi-active tags • Uses a built-in battery to power the circuit only when a reader first energizes the tag • Size of the memory in a tag varies between 16 bits and hundreds of kilobits • Tags are initially programmed with a unique identification code obtained from EPCglobal • Smart labels – Flexible RFID tag packages • Smart labels (cont’d) – Can be read regardless of their position or orientation • Major advantage of RFID over bar codes • 1-bit tags – Passive devices used in retail stores – Do not contain a unique identification code, a chip, or any memory – Simply used to activate an alarm • Chipless tags (known as RF fibers)

– Use fibers or materials that reflect a portion of the reader’s signal back • Sensory tags – Can be equipped with various kinds of sensors to monitor and record environmental information • Can monitor attempts to tamper with a product • Cost of a tag can vary greatly – Depending on type and number of tags purchased • There are four classes of tags – See table on following slide • Readers (also called interrogators) – Devices that connect with the company’s network and transfer data obtained from the tags to a computer – Some readers can also write data onto tags – Readers that work with passive tags also provide energy that activates the tags – Read distance is determined by the size and location of the tag and the reader antennas • As well as the amount of power transmitted

Antennas • RFID antennas used in tags may be limited in size due to the dimensions of the tag itself • Types of antennas – Linear: offer greater range but less accurate reads – Circular: have greater read accuracy, especially in applications in which the orientation of the antenna varies • Have a more limited range • Larger antennas allow the tags to be read at greater distances – As frequency increases, the wavelength gets smaller as does the antenna • Higher frequency antennas can be made relatively small – Still allow the tags to be read at greater distances • Reader antennas have to be designed for the specific type of application • No “typical” style of RFID antenna exists Software • Type of software depends on the specific RFID application • Categories of software components – System software: used to control hardware functions, implement communication protocols, and control data flow between tags and readers – Middleware: responsible for reformatting data from readers to business applications

– Business application software: responsible for processing orders, inventory, shipments, invoices, etc. EFC Global Network Services • EPCglobal Network Service – EPC reduces need for cross-referencing • Object Name Service (ONS) – A mechanism for discovering information about a product and related services – When a reader gets the EPC from a tag: • Passes it to the company’s servers, which send it to ONS via the Internet • ONS identifies the manufacturer and responds with the URL of the server where product information is stored • EPC Information Services (EPCIS) – Will enable large organizations to purchase, invoice, and track product orders over the Internet – Will eliminate the need to send paper documents by mail or fax – Similar to the Electronic Data Interchange (EDI) specifications that many large companies use to complete paperless transactions How RFID Works • Tags and readers use different transmission mechanisms in each frequency band • This section of the text introduces the technical details of how two of the most common types of passive tags and readers communicate – UHF (400 to 900 MHz) – HF (13.56 MHz) PHY Layer • Coupling – The connection between a passive tag and reader • Two types of coupling – Inductive or magnetic coupling: designed for tags that touch the surface of the antenna or are inserted in a slot in reader’s case

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