The life and times of an RFID chip

McCarran International Airport in Las Vegas, which handles more than 68,000 pieces of luggage daily, is committed to buying 100 million RFID tags over the next five years, according to Samuel Ingalls, assistant director of Aviation, Information Systems at McCarran. This is the story of one of those chips. We'll call it Chippy.

McCarran International Airport in Las Vegas is launching a $125 million program to embed RFID chips in baggage tags as a way to meet post-Sept. 11 security screening mandates and to improve the accuracy of baggage handling at the airport.

McCarran, which handles more than 68,000 pieces of luggage daily, is committed to buying 100 million RFID tags over the next five years, according to Samuel Ingalls, assistant director of Aviation, Information Systems at McCarran.

This is the story of one of those chips. We'll call it Chippy.

Designing Chippy

The design of an RFID chip depends on its intended use, says John Shoemaker, vice president of business development for transportation and aviation solutions at Symbol Technologies.

"There are different chips for different applications," he says. "In the process of making the chip, you need to be clear on the architectural design."

McCarran chose an architecture developed by Matrics, which was acquired by Symbol last year. Chippy will be a Class 0 UHF tag that is read-only and operates in the 900-MHz range. Ingalls says he chose this design because read-only RFID tags offer high levels of security , don't require batteries or line of sight and can be read from up to 25 feet away. Also, the passive tags are less expensive - as little as 20 cents per tag - than their battery-powered counterparts, which can run $20 to $100 each.

Shoemaker says the gestation period for an RFID chip can be up to six months or more. "You have to do a pilot and run prototypes," Shoemaker says. Matrics spent more than a year and millions of dollars to develop the passive UHF RFID chip and bring it to production, he says.

Before committing to the chip design and overall project in October of 2004, McCarran put Symbol/Matrics through a several-months-long RFP process. "We had the screening requirement post 9/11 and we became sure pretty early on that that we wanted to move to RFID rather than stay with bar codes," Ingalls says.

A chip is born

Chippy, like all of its semiconductor brethren, began its life as sand. Symbol contracts with manufacturing plants in China, Japan and Taiwan to create silicon chips. For the McCarran project, Symbol chose Taiwan Semiconductor Manufacturing Co. (TSMC), one of the largest chipmakers in the world.

The chips use radio frequency design techniques - there is such intricate circuitry that it's mind-boggling, Shoemaker says.

The circuit board chips, which are no bigger than a grain of sand, are placed on a semi-conductor wafer. Shoemaker says 30,000 to 60,000 chips are housed on each wafer, which is about 8 inches and circular. He adds that each semiconductor manufacturing plant can churn out billions of chips each week.

Once the wafers are complete, TSMC ships them to Symbol's San Jose facility to be paired with the antenna needed for signaling. Symbol couples the antenna and the chip on a substrate inlay. The chip is applied to the inlay - which is already outfitted with a 1-ounce antenna - using an adhesive.

Chippy measures 2-by-4 inches, although other tags that require a greater read distance could be as large as 4-by-4 inches, Shoemaker says. "If you need to read a tag from more than 25 feet away, even though the tag has no battery and is reflecting a signal, you'll need a bigger inlay or use more powerful signals from the reader." He adds that read ranges up to 50 feet have been demonstrated, but must be approved with a special license from the FCC. Nearly all the current installations are FCC-compliant at 1 watt of power (similar to a cell phone) and do not need a special license.

The next step is to send Chippy to a label maker, where the inlay is embedded in a traditional paper bag tag, complete with the traditional adhesive backing. "Unless you opened up the bag tag and saw the antenna, you'd never know it was there," Shoemaker says.

Ingalls agrees. He says only passengers holding the tags up to the light would be able to see the antenna embedded in the tag. The tags weigh no more than 2 ounces and are equivalent to the 21-inch stock normally used by airlines to label bags.

Chippy gets a job

Once the tags are complete, they are ready to be shipped to the customer - in this case, McCarran. Ingalls says he leaves the intricate details of how the labels are embedded with RFID chips to Symbol. "We wanted one vendor to take the hit - not deal with a bunch of vendors," he says.

Chippy arrives at the McCarran warehouse in Las Vegas as part of a 175-tag roll of labels. "We actually have set up a schedule with Symbol for them to be delivered on a regular basis over the next few years," Ingalls says.

Ingalls and his team manage all the networks in the airport - airline check-in, baggage handling. He says this centralization makes it easy to roll out the RFID technology airport-wide. Ingalls distributes the new bag tags, printers, RFID readers and other equipment to the airlines, baggage handlers and other necessary users.

Already, Ingalls has started retrofitting check-in agent stations with Vidtronix printers to support the embedded tags. When passengers arrive at the terminal, they place their luggage on the scale as usual. The agent checks them in, prints out an RFID-enabled tag and affixes it to the luggage.

The read-only chip in the tag features two important pieces of information - the three-letter airport code (in this case, LAS) and a pre-printed 10-digit identifier. Ingalls says having only this information is important for the privacy of passengers. If someone were to try to read the tag, he would not be able to get any personal data about the passenger.

At check-in, that 10-digit identifier is mapped to the passenger in the airport and to the airline tracking systems. The identifier then links the baggage to important information regarding destination, origination point, connections, flights, security status, etc. The tags are also still printed with the traditional bar code and other visible information for all the systems still using legacy optical technology.

"From the standpoint of populating information into the database, it isn't much different than the bar code," Ingalls says.

Once the agent makes sure that the tag is "live," using an RFID reader, the bag is put on a conveyor belt and sent to security screening.

"Here the bag begins a long, complex journey," Ingalls says.

Chippy goes for a ride

After Sept. 11, airports and airlines were given strict mandates about security screening for luggage. At the time, McCarran's screening was decentralized. To meet the new regulations, the airport is constructing a state-of-the-art centralized security system that will feature six, two-level screening facilities with four miles of conveyors.

"It's a large, complex system broken down into screening nodes," Ingalls says. The screening nodes require 70 different reader and antennae arrays to read the bag tags.

"There is an array of antennas around each segment of baggage conveyor," he says. Within each array there are four antennas around the frame of the conveyor - above, below and on both sides. "The redundancy ensures that no matter which way the antenna is pointing, the tag can be read."

Bags entering the screening facility are subject to different types of security scans, such as bomb detection. The RFID tags enable the bags to navigate the system automatically - with readers at every critical juncture.

The readers can scan a tag that has been crumpled, trapped inside a zipper, or partially destroyed. "We want to make sure the system is tough and impervious to damage," Ingalls says.

The RFID tags offer a 99.8% accuracy read rate, unlike their bar code counterparts, which are only at around 85% accuracy. Bar codes must be line of sight and are useless if marred or blocked in any way. If a bag is upside down or turned around on the conveyor, the bar-coded tag is basically useless. This causes headaches for the airport system, including the potential for bags to miss flights.

When Chippy enters the security facility, it introduces itself to the system via a reader. This determines that the bag has a unique identifier and is valid. The reader also checks to make sure that the tag is from the McCarran system and not somewhere else.

Once Chippy is matched to the system, the luggage proceeds along the conveyor to various checkpoints. At each, the tag is read and a time-stamp is written back to the database, creating a trail.

"If a bag has been identified for additional screening or manual search, it would be diverted automatically through the conveyor system," Ingalls says. "There is no manual involvement."

When the baggage reaches the end of its individual security screening checklist, it must be reunited with its flight. The tag readers help navigate the bag through the conveyor system to a carousel where the flight baggage roster is created. That drop-off point is recorded into the Oracle database so the baggage handlers are aware that it is ready for boarding and the airlines can track the average time it takes a bag to go through screening.

Leaving Las Vegas

For Chippy, this is the end of its usefulness for McCarran Airport. But Ingalls hopes that airlines will take advantage of the embedded chips "upstream" to help passengers track their bags and to speed frequent- flyer check-ins. He also thinks RFID technology eventually will help reduce the minimum connection time that airlines need for baggage to transfer flights.

Already, Ingalls sees the benefits of the RFID technology. The 99.8% accuracy rate of tag reading alone will save the airport and airlines hundreds of thousands of dollars each year. Lost or delayed luggage costs the airlines an average of $100 per passenger. This price includes courier services to get luggage to the passenger or fees to replace items. The airports also have to pay for baggage handlers to sort out problems when they arise. Ingalls says even a 10% failure to read bag tags results in 6,800 bags having to be dealt with manually. "That's a four-mile line of bags that someone would have to deal with," he says.

Ingalls adds that he's working alongside McCarran's tenant airlines, which are all actively looking at RFID for their own operations. "We tried to architect a system that is open from a standards standpoint and flexible and scalable. Right now, the chip's usefulness ends at the flight, but in future months and years, airlines will use that chip for all sorts of advances."

And McCarran does not want to be an island in its use of RFID. "Soon there will be millions of [tagged] bags going into other airports," Shoemaker says. "The goal is to connect all those airports to create an expanding capability that will benefit all of aviation globally."

Once the bags leave McCarran, Chippy's fate is unclear. The tag could be on a flight to Boston or Berlin or Bangkok. The luggage could belong to a convention-goer, a gambler, or a couple who tied the knot. Once travelers retrieve their bags at the destination airport, Chippy could be ripped off and tossed away immediately. Or the tag could sit on that piece of luggage in a dark closet for months. Or Chippy might live on in somebody's wedding scrapbook.

Gittlen is a freelance technology editor in Northboro, Mass.She can be reached at

Copyright © 2005 IDG Communications, Inc.

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