Letter of Transmittal: Individual Research Project Practical Implementation of Radio Frequency Transmitter Tags and Receiver Stations Final Project: Individual Research Paper New Jersey Institute of Technology Technical Writing ENG 352-001 Fall Semester, 2005 Abstract: The purpose of this project was to research how an RFID (Radio Frequency Identification) system works and to decide how to apply that knowledge in the design of a RF system. An RFID system is a structure to keep track of large numbers of objects by encoding the unique information onto an attached tag. A radio signal is sent from a transceiver to the tag, which returns a modulated (depending on the designed specifications) signal carrying information to be processed by the transceiver’s computer. A radio signal is sent from the transponder (tag) using a small antennae to a transceiver station. This radio signal is sent via an electrostatic coupling in the tag through the RF portion of the electromagnetic spectrum. The information send through the signal is contained on a circuit at the center of the tag. Depending on the application, complexity of data, and number of active objects an active or passive RFID can be chosen. A requirements analysis was detailed along with the priorities for each requirement, and these specification were used in conjunction with the research to outline selections for an RF system. For the application, a ID-card type passive RF tag of Extremely Low Frequency (300 KHz) was chosen along with the Chipcon CC1010 programmable RF transceiver. R Ranky 1 RF Tags
Transcript
Letter of Transmittal:
Individual Research ProjectPractical Implementation of
Radio Frequency Transmitter Tags and Receiver Stations
Final Project: Individual Research PaperNew Jersey Institute of TechnologyTechnical Writing ENG 352-001Fall Semester, 2005
Abstract:
The purpose of this project was to research how an RFID (Radio Frequency Identification) system works and to decide how to apply that knowledge in the design of a RF system.
An RFID system is a structure to keep track of large numbers of objects by encoding the unique information onto an attached tag. A radio signal is sent from a transceiver to the tag, which returns a modulated (depending on the designed specifications) signal carrying information to be processed by the transceiver’s computer. A radio signal is sent from the transponder (tag) using a small antennae to a transceiver station. This radio signal is sent via an electrostatic coupling in the tag through the RF portion of the electromagnetic spectrum. The information send through the signal is contained on a circuit at the center of the tag.
Depending on the application, complexity of data, and number of active objects an active or passive RFID can be chosen.
A requirements analysis was detailed along with the priorities for each requirement, and these specification were used in conjunction with the research to outline selections for an RF system. For the application, a ID-card type passive RF tag of Extremely Low Frequency (300 KHz) was chosen along with the Chipcon CC1010 programmable RF transceiver.
Submitted by: Richard Ranky
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December 6th, 2005
To: Prof. Brenda Moore
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Individual Research ProjectPractical Implementation of
Radio Frequency Transmitter Tags and Receiver Stations
Richard RankyNew Jersey Institute of TechnologyENG 352-005Final Research ProjectProf. Brenda Moore Dec. 6th, 2005
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Table of Contents:
Abstract page
Introduction page
Discussion page
Conclusions page
References page
Appendix page
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Abstract
The purpose of this project was to research how an RFID (Radio Frequency Identification) system works and to decide how to apply that knowledge in the design of a RF system.
An RFID system is a structure to keep track of large numbers of objects by encoding the unique information onto an attached tag. A radio signal is sent from a transceiver to the tag, which returns a modulated (depending on the designed specifications) signal carrying information to be processed by the transceiver’s computer. A radio signal is sent from the transponder (tag) using a small antennae to a transceiver station. This radio signal is sent via an electrostatic coupling in the tag through the RF portion of the electromagnetic spectrum. The information send through the signal is contained on a circuit at the center of the tag.
Depending on the application, complexity of data, and number of active objects an active or passive RFID can be chosen.
A requirements analysis was detailed along with the priorities for each requirement, and these specification were used in conjunction with the research to outline selections for an RF system. For the application, a ID-card type passive RF tag of Extremely Low Frequency (300 KHz) was chosen along with the Chipcon CC1010 programmable RF transceiver.
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Introduction
Topic and Motivation:
The topic for this research paper is the theory and practical application of Radio-Frequency Transmitters and receivers.
This paper covers the various types of RF systems, and their practical uses in day-to-day life. To a Mechanical Engineer the research in itself is useful for a better understanding of this type of electrical system. Since the M.E. curriculum does not cover many electrical engineering theories it will provide a good fundamental knowledge of one of the most wide-spread electrical systems of today.
The second reason is a practical application to a personal project. This research should be able to be applied to a product currently in the design phase which should eventually be manufactured and sold commercially. For this reason, the conclusions section evaluates the practical application of this research.
Scope:
The purpose of this research defines the scope of the project. The most attention will be given to knowledge which can be applied to the product, as oppose to knowledge which does not have any serious practical value in the product.
The Product:
Since no name has yet been decided, it will simply be referred to as ‘The Product’. The idea is for a device to identify between several different moving objects within a particular radius. It must be able to react to particular objects, and disregard others.
As an example, consider a building of people with a door operated by a mechanical actuator. If every person has some sort of identification tag or wristband, when they pass within a certain radius of the door, the system should be able to identify between persons for which to open the door (by sending a signal to the actuator) and those who do not have access. The following chart displays the requirements analysis of the system:
System Requirement Importance (1-5)Fully Automated 5Reliability upwards of 90% 4Maintenance not exceeding three times a year 5Minimal Cost of parts and Installation 2Function with a group of up to 200 Objects 5Minimal Complexity of Equipment 2Maximum Range of approximately 20 feet 2
Chart 1: Requirements Analysis
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Please note that this chart was also used as a criterion for deciding if a piece of information was pertinent to this research paper.
Qualifications:As a Mechanical Engineering student I have been taught the fundamentals in electro-mechanical systems, and I have already worked in the professional field at an Engineering Design Studio. Through experience in research, technical writing, and product design (combined with a strong academic foundation) I will make informed, logical decisions on how to apply my research.
Conclusions to be Derived:At the end of the paper, the various options for implementation of RF tag systems will be outlined, and one in particular will be recommended as a solution to the product being designed.
An RFID system is a structure to keep track of large numbers of objects by encoding the unique information onto an attached tag. A radio signal is sent from a transceiver to the tag, which returns a modulated (depending on the designed specifications) signal carrying information to be processed by the transceiver’s computer.
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Discussion
History:
In 1939 the IFF transponder was invented by British forces as a means for the allied forces to identify between aircraft as friend or foe. This worked by each aircraft sending a signal through a transponder (see below) to a receiver station on the ground. (Shultz 17)
In 1999 MIT led a study as to how networks and businesses can benefit from the wide-scale use of what had become the RFID. It was meant as the replacement for the barcode scan system currently in operation throughout the world.
Although the system has become more and more widespread and applications nowadays range from identifying a single object in a building to tracking thousands of different objects across a country.
Basic Principals and Theory:
The purpose of an RFID system is to enable data to be transmitted by a mobile device (called a tag) which is read by an RFID reader and processed according to the needs of a particular application.
The term RFID stands for Radio Frequency Identification. A radio signal is sent from the transponder (tag) using a small antennae to a transceiver station. This radio signal is sent via an electrostatic coupling in the tag through the RF portion of the electromagnetic spectrum. The information send through the signal is contained on a circuit at the center of the tag.
Radio frequency transmission works on the principle that when RF current is applied to an antennae an electromagnetic field is created and propagated. The wave itself is a form of electromagnetic radiation, created when a charged object (in this case an electron) accelerates with a frequency in the RF range. In radio transmission this acceleration is caused by an alternating current in the antennae.
The following diagram (figure 1) and chart display the range of radio frequencies in the electromagnetic spectrum:
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These frequencies make up part of the electromagnetic radiation spectrum: Ultra-low frequency (ULF) -- 0-3 Hz Extremely low frequency (ELF) -- 3 Hz - 3 kHz Very low frequency (VLF) -- 3kHz - 30 kHz Low frequency (LF) -- 30 kHz - 300 kHz Medium frequency (MF) -- 300 kHz - 3 MHz High frequency (HF) -- 3MHz - 30 MHz Very high frequency (VHF) -- 30 MHz - 300 MHz Ultra-high frequency (UHF)-- 300MHz - 3 GHz Super high frequency (SHF) -- 3GHz - 30 GHz Extremely high frequency (EHF) -- 30GHz - 300 GHz
(Shultz 58)
There are four main frequency bands for RFID tags commonly in use, categorized by their radio frequency:
Low frequency tags (125 or 134.2 kHz) High frequency tags (13.56 MHz) UHF tags (868 to 956 MHz) or 433 MHz Microwave tags (2.45 GHz) or 5.8 GHz).
UHF tags can be used globally when specially tailored according to regional regulations as there are no globally unified regulations for radio frequencies in this ISM band range.
The most common design of an tag uses the Inductively Coupled RFID architecture:
Silicon microprocessor – A chip at the center of the tag which can vary in size depending on the amount and complexity f information stored
Metal coil – A coil made of copper or aluminum wire that is wound into a circular pattern on the transponder. This coil is the tag's antenna. The tag transmits signals to the reader, with read distance determined by the size of the coil. Most coils operate at 13.56 MHz.
Encapsulating material – A cover for the entire system. This could be anything from plastic to glass, but needs to have a minimal conductivity so as not to interfere with the signal’s reception or transmission.
Figure 2: A top-down view of a passive RF tag used to keep track of library books.
Inductive RFID tags are not self-powered, and thus are essentially useless without the reader. The power used to transmit signals is the magnetic field generated by the reader (and received by the antennae). The tag picks up the magnetic energy, current passes through the microprocessor, the signal is modulated slightly, and sent back to the reader. The reader then directs the signal to the host computer, which decided what to do with the information depending on the software.
System Architecture:The following is a standard Event Processing Architecture for RFID
Stage 1: Event EngineOnce an event (signal received) moves through the collection phase, it can be processed according to type. The event engine executes various actions based on what type of signal is received. This process can range from sending the signal to a database software to activating an electromechanical device.
Stage 2: Event DatabaseAll relevant events are sent to the event database for sorting and storage. Rather than allow events to be simple transitory entities, the event engine has the ability to record each event, either in its raw form or in a
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processed form, in a scalable, distributable event database. This database forms a historical archive for event processing. This database is used for statistical analysis like observing trends over a period of time.
Stage 3: Event ServerAlthough the information is stored, a link to the human user is necessary. The server provides a flexible interface to the event engine, allowing integration of different coding standards (to alter an event engine) and event query tools (to observe the event database).
Figure 3: An example of code for an event engine (Trigg 13)
RFID System Components:
Transceiver: In radio communications, a transceiver is a two-way radio that combines both a radio transmitter and a receiver that sends/received information in half-duplex mode from a base station. The transceiver is directly connected to the computer with the three event stages. Half-Duplex mode refers to the transmission of data in only a single direction at any given time. A walkie-talkie is a good example of such a system (as oppose to a phone). The reasoning behind using a half-duplex rather than a full duplex is so as not to interrupt the inbound signal from the tag with a new outbound signal from the transceiver.
Transponder: = RFID Tag = receives signalA transponder is another term used to describe the tag. This device receives the signal, modulates it according to the specifications within the self-contained microprocessor and sends the new signal back to the transceiver.
Depending on the function of the power supply, RFID labels can be passive, active, or a combination.
Passive RFID tags have no internal power supply. The minute electrical current induced in the antenna by the incoming radio frequency signal provides just enough power for the CMOS integrated circuit (IC) in the tag to power up and transmit a response. Most passive tags signal by backscattering the carrier signal from the reader. This means that the aerial (antenna) has to be designed to both collect power from the incoming signal and also to transmit the outbound backscatter signal. Lack of an onboard power supply means that the device can be quite small: commercially available products exist that can be embedded under the skin.
As of 2005, the smallest such devices commercially available measured 0.4 mm × 0.4 mm, and is thinner than a sheet of paper; such devices are practically invisible.
Because passive tags are the cheapest to manufacture and have no battery, the majority of RFID tags in existence are of the passive variety. As of 2005, these tags cost an average of 7.5 cents in volumes of 1 million units or more. Predicted high demand for these tags is expected to lower the cost to 4 cents by the year 2015 (not accounting for inflation).
Semi-passive RFID tags are very similar to passive tags except for the addition of a small battery. This battery allows the tag IC to be constantly powered. This removes the need for the aerial to be designed to collect power from the incoming signal. Aerials can therefore be optimized for the backscattering signal. Semi-passive RFID tags are faster in response and therefore stronger in reading ratio compared to passive tags.
Active RFID tags or beacons have an internal power source which is used to power any ICs and generate the outgoing signal. This allows many to have longer range and larger memories than passive tags, as well as the ability to store additional information sent by the transceiver. To economize power consumption, many beacon concepts operate at fixed intervals. At present, the smallest active tags are about the size of a coin. Many active tags have practical ranges of tens of meters, and a battery life of up to 10 years. The other main advantage of active tags over passive ones is the ability to re-write data on the microprocessor, creating a system using object more like mini-computers.
RFID tags can be very expensive on a per-unit basis, costing anywhere from $1 for passive button tags to $150 for active battery-powered, read-write tags. Although keep in mind that these are per-unit and if you observe most department stores remove the larger (active) RF tags to be re-programmed and re-used later on. The high cost for these tags is due to the silicon, the coil antenna and the process that is needed to wind the coil around the surface of the tag. Accuracy and Precision:Reading ratio close to 100% is a mandatory requirement for successful application.
Although the cost of passive tags are nearly one hundredth of active tags, other factors including accuracy, performance in harsh environments (around water or metal), and
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reliability make the use of active tags still very common today. The final quality unfortunately never reaches the 100% ratio, but in most cases will be upwards of 96%.
Current Applications:
RFID systems can be used just about anywhere, from clothing tags to missiles to pet tags to food. Any occasion that requires a unique identification system. The tag can carry information as simple as a pet owners name and address or the cleaning instruction on a sweater to as complex as instructions on how to assemble a car.
Existing RFID frequency standards used in the United States: 125 kHz (the original standard) and 134.2 kHz (the international standard).
Current usages:
Talking Prescriptions - 13.56 MHz tags have been placed on prescriptions for Visually Impaired Veterans. The Department of Veterans Affairs Outpatient pharmacies are now supplying the tags with label information stored inside that can be read by a battery powered, talking prescription reader. This reader speaks information such as: Drug Name; Instruction; Warnings; etc.
Some auto manufacturers use RFID tags attached to the chassis of cars moving through an assembly line. At each successive stage of production, the RFID tag tells the computers what the next step of automated assembly is, and what has been completed so far.
Low-frequency RFID tags are commonly used for animal identification. Pets can be implanted with small chips so that they may be returned to their owners if lost.
Two High-frequency RFID tags are used in library book or bookstore tracking, pallet tracking, building access control, airline baggage tracking, and apparel item tracking. High-frequency tags are widely used in identification badges, replacing earlier magnetic stripe cards.
RFID tags are already used for electronic toll collection at toll booths across the States, Israel, the Philippines, and Chile. Active tags are read remotely as vehicles pass through the booths, and tag information is used to debit the toll from a prepaid account. The system helps to speed traffic through toll plazas.
Location sensing of RFID with milimeter accuracy is possible by adding a low cost photosensor. The real time location sensing (RTLS) supports many complex geometric queries. In January 2003, Michelin began testing RFID transponders embedded into tires. After a testing period that is expected to last 18 months, the manufacturer will offer RFID enabled tires to car makers. Their primary purpose is tire-tracking in compliance with the United States Transportation, Recall,
Enhancement, and Accountability. Sensors contained within the tires will document wear, resilience, and use of the tires.
Starting with the 2004 model year, a Smart Key option is available to the Toyota Prius and some Lexus models. The key fob uses an active RFID circuit which allow the car to acknowledge the key's presence within 3 feet of the sensor. The driver can open the doors and start the car while the key remains in a purse or pocket.
RFID vs Barcodes:
Although barcodes will almost always win on cost, they have several disadvantages when compared to RFID tags:Unlike barcodes, which are a standard right now, RFID labels have the advantage of containing other data besides the price like the product characteristics, temperature, and the date it was moved from one place to another.
One of the key differences between RFID and bar code technology is RFID eliminates the need for line-of-sight reading that bar coding depends on. Also, RFID scanning can be done at greater distances than bar code scanning. High frequency RFID systems (850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz) offer transmission ranges of more than 90 feet, although wavelengths in the 2.4 GHz range are absorbed by water (and the human body) and therefore has limitations. (AIM Global)
Barcodes are also a read-only technology since they possess no means of sending a signal. Barcodes must also be scanned one at a time whereas an entire room of RFIDs can be scanned within the span of only a few seconds (at the most),
Limitations and Ranges of Activity:
The disadvantage to this kind of tag is that it has a very limited range. The range of Motorola's BiStatix tags is limited to just about 1 cm (.39 inch). Making the tag cover a larger area of the product packaging will increase the range, but not to the extent that would be ideal for the system that retailers would want. In order for a global system of trillions of talking tags to work, the range needs to be boosted to several feet or more. A company called Intermec has developed RFID tags that meet these needs, but that still very expensive compared to current market options. Researchers at several companies are looking for ways to create a tag with a range of several feet, but that costs about the same as bar code technology. In order for retailers to implement a widespread RFID tag system, the cost of the tags will have to get down to one penny (1 cent) per tag.
On the bases of the requirements analysis the following RF system was outlined:
An ID-card type passive RF tag of Extremely Low Frequency (300 KHz) to work in conjunction with the Chipcon CC1010 programmable RF transceiver.
The specifications for this transceiver fit all of the requirements, and allow the system to comfortably conform to the initial goals. The only requirement that will not be met as effectively as originally hoped is the range of operation, but this was only rated as a 2 on the requirements, so the deviation is acceptable.
This system would meet the current government standards for use within the United States, and due to the low frequency used would not have any adverse health effects to the personnel using them. The choice to use a passive tag was to conform to the cost requirement. The system will be fully automated during operation since the signals sent and received will be controlled by transceiver, permanently connected to a server running 24 hours a day. Passive tags have a lifespan of several years, and even using a PC with a Pentium IV chip service would only need to be three times a year (probably even less for a new machine).
System Requirement Importance (1-5)Fully Automated 5Reliability upwards of 90% 4Maintenance not exceeding three times a year 5Minimal Cost of parts and Installation 2Function with a group of up to 200 Objects 5Minimal Complexity of Equipment 2Maximum Range of approximately 20 feet 2
RFID Online Journalhttp://www.rfidjournal.com/November 30th, 2005
Case Studies:Trigg, John B. “An Architectural Overview and Case Review”http://www.progress.com/realtime/docs/whitepapers/arch_overview_rfid_jtrigg2.pdfDecember 1st, 2005
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Appendix A:Specifications for ChipCon CC1010 RF Transceiver
CC1010 Product InformationA true System-on-Chip (SoC) solution CC1010 - The industry's first truly complete RF System-on-Chip solution! On a single die, the award winning 300 to 1000 MHz CMOS CC1000 RF Transceiver has been integrated with an industry standard 8051 microcontroller core. The CC1010 integrates a very low-power 300 to 1000 MHz RF transceiver and a 8051-compatible microcontroller that has 32 kB in-system programmable Flash, hardware DES encryption/decryption and a three channel 10-bit ADC. This means only a few external passive components are necessary to make a powerful embedded system with wireless communication capabilities, sensor interfacing possibilities and a lot of processing power.
Key Features:
300-1000 MHz RF Transceiver· Very low current consumption· High sensitivity (typically -107 dBm)· Programmable output power up to +10 dBm· Data rate up to 76.8 kBit/s· Very few external components· Fast PLL setting allowing frequency hopping protocols RSSI· EN 300 220 and FCC CFR47 part 15 compliant 8051-Compatible Microcontroller· Typically 2.5 times the performance of a standard 8051· 32 kB Flash, 2048 + 128 Byte SRAM· 3 channel 10 bit ADC, 4 timers /2 PWMs, 2 UARTs, RTC, Watchdog, · SPI, DES encryption, 26 general I/O pins.
Supported by easy to use development tools2.7 - 3.6 V supply voltage64-lead TQFP
