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Radio frequency waves have powered lots of advances over the years, including microwaves, cordless phones, and computer networks. Now a Pitt engineering professor and his students are causing some waves of their own. Their innovations ultimately may improve our lives—from shopping to medical treatments.

Out of Thin Air


Rob Amen


 
  Marlin Mickle, the Nickolas A. DeCecco Professor in the School of Engineering, is working to harness radio frequency waves for new applications that could have vast benefits.
 

Marlin Mickle, an engineer and inventor, guides a clattering shopping cart down an aisle at a local grocery store in Oakmont, Pa. He’s an attentive shopper, his alert blue eyes scanning the shelves through wire-framed bifocals. As he places items into his cart, he crosses them off his hand-scribbled grocery list using a pen pulled from the dress-shirt pocket near his trademark suspenders and matching tie. Soon, Mickle scratches off the last entry on his list and takes his place in the checkout line.

It’s a ritual performed every day by millions of people who walk the aisles of stores, pull products from shelves, check items off lists, then head toward a cash register, where—most of the time—they wait. But what shoppers at the Oakmont grocery store don’t know is that this unassuming man in line with them is engaged in research that may one day make such waiting obsolete. Mickle, the Nickolas A. DeCecco Professor in the School of Engineering, is working to harness radio frequency waves for new applications that could have vast benefits, far beyond store checkout lines.

Harnessing radio waves for practical use is hardly a new phenomenon. Inventors have been exploring potential applications for more than 100 years. Today, cordless phones, microwaves, computer networks, wireless hubs, and many other devices all use radio frequency principles. But recent advances suggest that radio waves will likely become the platform for a range of new technologies and products.

Mickle is helping to make that happen. For instance, he and the University of Pittsburgh are at the epicenter of an advance in radio frequency identification, or RFID. Working with his students, Mickle continues to pursue breakthroughs in the field, and Pitt’s RFID Center for Excellence—opened in September 2005—has established the University as one of the top three institutions worldwide in RFID research, along with the Massachusetts Institute of Technology (MIT) and the University of Cambridge in England.

RFID technology, which has existed for decades, uses a radio-wave-based method to tag objects electronically, then extract and transmit information from them. RFID is already being used for applications like the EZ Pass system, which allows vehicles equipped with tags to zip through special toll booths that wirelessly “read” the tags and bill the toll charges to drivers’ EZ Pass accounts—no stopping or waiting required. Researchers around the country are working to develop and refine the technology that makes this wireless “tagging” possible, and Mickle’s efforts at Pitt are at the forefront of a new RFID approach that holds particular promise.

Radio waves are a form of light in the electromagnetic spectrum. They surround us, but they are useless without a way to take them out of the air, says Mickle, who directs Pitt’s new RFID center as well as the School of Engineering’s Swanson Center for Product Innovation. He compares the technology to drawing electricity out of an outlet in a wall. “If you want to get electricity out, you need a plug,” he says, “and the plug has to be the right fit.” An RFID tag typically consists of a programmable microchip and a tiny antenna that receives and sends radio frequency wave transmissions. The antenna acts as the plug—the conduit for the radio waves.

Typically, the antenna and microchip are separate; they’re attached together on a base, and that unit becomes the RFID tag. A separate device called a “reader” is located elsewhere. When the tag’s antenna is in the vicinity of an RFID reader, it’s prompted to intercept and send radio frequency waves. Radio waves from the reader activate the tag, which then reflects back much shorter radio waves, carrying the information held on the microchip. The reader converts the waves into digital data, which are passed on to traditional computers for use in standard billing and inventory systems.

Mickle—along with his Pitt students and colleagues, as well as industry partners—have developed some important innovations in the field. They have, for instance, found a way to embed a tiny spiral antenna onto a microchip, creating a single, compact RFID tag not much larger than a pen tip. Even more significantly, Mickle and his team have developed an improved method for receiving and sending RFID signals. By changing the frequency of the waves at a key point, the team has reduced signal interference, increased the strength of the signal sent to the reader, and harvested excess energy produced by the radio waves to self-power their RFID system. They’ve also determined how to place tiny sensors on their microchips, with the potential to gauge and perhaps modulate properties like temperature, pressure, and light.These innovations open the way for improved efficiencies, lower costs, and even entirely new uses of RFID technology.

Currently, when a product arrives at a store, a bar code is affixed to the product. Every box of Cheerios, for instance, carries the same bar code information. At the store checkout, a clerk places the bar code in front of an infrared scanner, which identifies the product and price on the clerk’s computer register. Using this system, the register tallies the shopper’s total, item by item. That’s how things work at Mickle’s grocery store and most other stores around the nation.

RFID could change all of that. Instead, each product container would get an RFID tag at its point of origin, enabling products to be tracked from the factory directly to the store, then to shelf placement, and finally to point of sale—all wirelessly. Store managers would have instant access to product data via computer, 24 hours a day. If stores also were equipped with RFID readers in various positions at their entrances, then shoppers could simply steer their carts out a store’s entrance, where the readers would extract labeling and price information from each of the product tags, then charge the costs, by prearrangement, to shoppers’ debit cards or store accounts, all in milliseconds. No more lengthy waits in checkout lines. But that’s hardly the limit of RFID’s potential benefits.

Experts like Mickle—who is founding editor of the International Journal of Radio Frequency Identification Technology and Applications, the first academic journal in the field—believe that RFID has the potential to save stores and suppliers millions of dollars. In fact, the world’s leading Fortune 500 company, Wal-Mart, is already using the technology to streamline its distribution operations.

Several years ago, Wal-Mart began exploring RFID as a way to tighten controls and costs on product shipping and tracking. The company realized that the technology could potentially eliminate costly warehouse distribution. “Companies lose money on everything they have in inventory,” Mickle says. The alternative is to operate on a just-in-time basis, ordering products from suppliers only as shelves begin to run low on those items. RFID makes that feasible.

“Suppose you knew when your various locations were going to need something. You could do away with the distribution center and send everything right to the location where it’s sold,” explains Mickle.

Essentially, he says, what Wal-Mart sells is shelf space, and it wants to keep the products flowing and the shelves full. Three years ago, the company mandated that its suppliers gear up for RFID, and several hundred of them are now equipped for basic wireless tracking. More will follow.

The technology has not yet advanced to enable RFID tag placements on each item in a supermarket or retail store—or even to the point where warehouses aren’t needed. But it does enable Wal-Mart stores and suppliers to track pallets of goods. The pallets are tagged and shipped from manufacturers to distribution centers. There, the pallets are unloaded and pass through shipment bays equipped with RFID readers. The readers scan the tags, and the information is immediately posted for managers to view as shipments depart and arrive.

As these small steps become routine, more sophisticated tagging and tracking will evolve, which is already the case in some other industrial, military, and government applications.

These kinds of demands in the commercial world are pushing RFID researchers to make the technology more efficient and less costly. “Wal-Mart really put the pressure on,” Mickle says, “because they were big enough to have a market that people paid attention to.”

Mickle never imagined he’d be involved in such a potentially influential enterprise as Pitt’s RFID center. His work with radio frequency (RF) waves began about eight years ago. Through a volunteer project, he involved his students in an exercise to help the elderly find lost hearing aids. Undergraduate Kevin Wells began experimenting with a wireless RF device, trying to figure out how to embed a transmitter in the hearing aid’s soft plastic. That challenge not only raised more questions but also more possibilities.

Soon, says Mickle, he realized the technology had immense potential. “It became clear we weren’t working on hearing aids anymore,” says Mickle, who is also a professor of electrical engineering, computer engineering, and telecommunications.

He turned his attention to tiny sensors and the possibility of transmitting information about temperature using an RF approach. NASA became interested along the way. Then, in late 2001, Mickle read that researchers in MIT’s groundbreaking RFID program intended to develop a tag with an antenna attached to a microchip in the next few years.

Years?, thought Mickle. Intended to develop? He and his Pitt team had already done exactly that. Word spread, and representatives from more than 100 companies, including Wal-Mart and Coca-Cola, poured into Mickle’s office wanting to learn more about how they could benefit from the breakthrough.

For the moment, Mickle is unsure when RFID tags will replace bar codes in the retail industry. Many significant obstacles remain, including major concerns raised by privacy advocates about a technology that can track and tally all kinds of information. Beyond that, the often-cited price of 20 cents or more per tag must drop to two or three cents before RFID use in stores could even be considered. To bring RFID to Wal-Mart’s shelves, about a trillion tags would need to be manufactured each year, according to Mickle’s estimates. About 250 billion would go to Wal-Mart, but suppliers likely would need to tag all of their items from a production standpoint, he says.

“There are a lot of zeros there. If this is going to work, it must be done using something other than silicon chips,” says Mickle, noting that such high demand would be difficult for the silicon industry to meet. He and his team are trying other approaches, like printing the tag’s electronic circuitry directly onto the product. This presents another big set of problems, because a product’s contents interfere with the data transmission from tag to reader—not to mention what happens when the shopping cart is piled with multiple products. But, says Mickle, that’s what University research is all about—answering the hard questions that no one else wants to tackle.

He remains focused on the science of RFID and RF rather than narrowing his research to solve specific problems, such as those in the retail sector. He continues his pursuit of improving the technology’s performance and expanding its reach. “The applications for this are far-reaching,” says Michael Lovell, the engineering school’s associate dean for research. “We’re on the tip of the iceberg.”

Already, some of Mickle’s students have worked with him and other Pitt faculty to develop an RF device that may help people with Bell’s Palsy, a form of facial paralysis. Their “Blink Project”—which uses RF chips embedded in a patient’s paralyzed eyelids and in the frame of accompanying eyeglasses to stimulate synchronous blinks—lessens the effect of the disease, and they’re refining the technology. A company on the West Coast approached Mickle to improve the process of providing neuromuscular stimulation to treat tremors in patients with Parkinson’s disease. The fruits of that RF research will soon be going to the FDA for approval for use in patients. Last summer, a team of high school teachers, funded by a National Science Foundation program, worked with Mickle’s team to develop an RF device to fight depression and epilepsy.

The possibilities for RF-based innovations are vast, and researchers worldwide are just beginning to scratch the surface of potential applications. Pitt’s new RFID center is hosting an international conference in September; and, already, three companies have been formed to commercialize the University’s RFID ventures.

In his office on the fourth floor of Benedum Hall, Mickle fields another phone call. It’s from the Department of Defense—could RFID be used to lighten, or eventually eliminate, the battery loads that soldiers carry in the battlefield? Today, groceries are not at the top of Mickle’s list.

 


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