The story behind the corporate espionage

Unless you are an engineer in the telecommunications industry (or are for some other reason extraordinarily knowledgeable about component technologies for consumer electronics), then chances are you have never heard of an FBAR filter .

But you probably have about 10 FBARs your pocket right now.

A ubiquitous addition to the modern cell phone, a film bulk acoustic resonator (FBAR) filter is a device that helps the modern smartphone user obtain faster data speeds across a broader spectrum. They also freed up space inside cell phones for other components—in the filter’s second, disruptive iteration, two-filter duplexers were about 1/400 of the size of the ceramic duplexers that they displaced. That size factor is now closer to 1/4000. As telecommunications networks upgraded from 3G to 4G over the last few years, billions of FBAR filters were produced by the Silicon Valley company Avago Technologies.

Such market penetration is one of the reasons why the American Institute of Physics (AIP) presented the 2014 AIP Industrial Application of Physics Prize to Avago physicist Paul Bradley and electrical engineers Richard Ruby and John Larson last month for their role in developing and commercializing the filters.

The timing of the award was especially interesting, given that a 32-count federal indictment , unsealed and handed down just days before, charged six individuals with economic espionage and theft of FBAR trade secrets for benefit of Chinese companies and universities. The indictment was the subject of front-page stories in the New York Times and the Wall Street Journal earlier the same week.

Nobody mentioned the looming case during the short awards ceremony at the Acoustical Society of America (ASA) 169th Meeting in Pittsburgh, but it must have been on many people’s minds.

“ASA has been a member of AIP since we were founded in 1931, so at this meeting it’s a great privilege to present the 2014 AIP Prize for Industrial Applications,” AIP Vice President Catherine O’Riordan said on stage.

Later that night I was fortunate to be a guest at the dinner party honoring the prizewinners, together with O’Riordan, the three winners and a few other AIP staff. There we discussed the technology and its history at length.

What is an FBAR filter?

An FBAR filter consists of about a dozen piezoelectric resonators each sandwiched between two electrodes. When the filters are multiplexed into combinations of two, six, or more filters, they route different incoming frequencies to the appropriate parts of the circuitry for cellular, WiFi, or GPS signals.

The routing allows phones to operate over multiple bands worldwide by narrowing the frequency bands that they connect to, thereby eliminating interference and allowing phones to transmit more effectively and clearly. The filters are also responsible for the reduction in the thickness of cellphones during the past decade, as well as for the seldom-heralded-but-quietly-relished ability to talk and browse at the same time.

Although they did not invent the FBAR itself, Bradley, Ruby, and Larson did invent the FBAR duplexer. They are also largely responsible for the FBAR’s widespread adoption as a technology. In some respects, their careers have mirrored the life of the product that they brought from adolescence to adulthood. FBAR was invented at Hewlett Packard, commercialized at Agilent Technologies, and is now Avago’s most successful product. Likewise, the three award winners started at HP, moved to Agilent, and currently work at Avago.

FBAR production keeps chugging along. On our way to the restaurant, Ruby pondered aloud, “I wonder how many FBAR filters have been made since we’ve been walking?” I happened to know the number of minutes in a year—525,600—thanks to the Broadway musical Rent. My dinner companions gave me the number of FBAR devices made every year and we estimated how long we’d been walking. A few quick mental calculations led us to conclude that 10 000 FBAR filters had been manufactured since we had left the hotel.

John Arnst is a media services writer at American Institute of Physics.

Update: 29 June 2015 3:36PM - A correction has been made to restore a paragraph regarding the Application of Physics Prize.