Engineering UHF RFID Systems

Course 201

Summary:

Radio Frequency Identification (RFID) is becoming one of the revolutionary technologies of our time promising to change the way we shop, and manage product flow through the supply chain.

RFID has many variations – this class will focus on UHF passive tags. These tags obtain all of their power from a transmitted RF field. They are the technology of choice for item level tagging.

During the first day, the student will learn the RF design processes needed to design and make RFID tags/ readers. This includes how to extract power from the incident RF field including the use of voltage doublers, matching antenna to the rectifiers for maximum power transfer, and the effects of different kinds of modulation schemes on the power transfer. He will learn the techniques that the tag uses to return information from the tag to the reader including various modulation techniques.

The second day will be devoted to the protocols needed to make these devices functional including the appropriate EPC standard, making dense tag field structures work using tree structures and Aloha networks. Improvements to the Aloha network will be developed showing how throughput can be increased quite dramatically. Techniques for estimating the size of the tag field will be developed. Finally, he will learn how to do applications design using these devices as a principal component.

Learning Objectives:

Upon completing the course, the participant will be able to:

Design RFID systems for various applications
Understand how to best obtain the needed power required to operate the tag
Understand the modulation techniques used in tags
Understand other problems such as multipath and polarization problems
Understand range issues and link budgets for these devices
Understand the requirements of the ISM bands including the need for frequency spreading.
Understand tree structures, throttling mechanisms, and Aloha networks – their advantages and limitations, and the reason they are needed.
Understand the EPC protocols
Understand algorithms that use a small sample to determine a close approximation to the number of tags in a tag field (and understand the necessity for doing so).
Understand techniques for improving the efficiency of Aloha networks

Target Audience:

For engineers who need a deep understanding of RFID technology such that they can design systems based on these devices.

Familiarity with RF circuit and systems design processes including receiver design, microwave design, power amplifier design, communication theory, and antenna design is highly desirable. Besser Associates offers classes on each of these topics.

Outline:

Day One

The Hardware Aspects—RF Design and Communications
• Obtaining Energy from an RF Field. Antenna Matching, Voltage Doublers, Power Output. • Modulation Techniques Appropriate to the Tag—ASK, PSK • Link Budgets • Multipath, Polarization Issues and How to Solve Them • Spread Spectrum Including Frequency Hopping • Antenna Design Including Directionality • Location and Mounting Issues.

Day Two

Protocols
• The Basic Problem. Tags are Simple, How to Make All But One Shut Up When The Entire Tag Field Is Addressed • The EPC Protocols • Sieving Techniques; Limitations and Advantages • Tree Structures; Limitations and Advantages • Aloha Networks; Limitations and Advantages • Algorithm for Estimating The Size Of The Tag Field—Necessary If One Wants To Read In A Reasonable Time All The Tags In A Large Tag Field • Algorithm for Improving The Efficiency Of Aloha Networks

Subject Areas Covered

RFID

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