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The life and times of an RFID chip

By , Network World
August 01, 2005 12:05 AM ET

Network World - 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.

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