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Patently successful

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January 7, 2011

As a graduate student, Dr. Prasad Shastry missed an opportunity to patent a tiny antenna that he invented, which is now being used by NASA and others worldwide.

So when the Bradley professor of electrical and computer engineering had another chance to patent something, he didn’t hesitate.

Shastry’s patent for an electronically tunable active duplexer was officially approved in the fall of 2009. That gives Shastry and Bradley full rights to the product for up to 20 years.

“It was exciting,” Shastry said. “I was pleased that the years of work had finally borne fruit in terms of the patent.”

An active duplexer is a small chip that enables simultaneous transmission and reception of signals while increasing the strength of signals as they are transmitted and received by wireless devices. Hence it is a bidirectional amplifier.

For example, cell phones currently use a switch to alternately connect to a transmitter and receiver in order to send and receive signals almost simultaneously. The signal strength is weakened as it passes through the switch.

Shastry’s active duplexer replaces that switch and enhances the signal strength of both incoming and outgoing signals. Boosting the signal strength allows communication over longer distances. And because signal strength can be boosted when it enters a wireless device, the sending device can deliver a signal of smaller strength, thereby saving energy.

The duplexer can be used in any wireless device, including cell phones, laptops and Bluetooth-enabled devices. Shastry and former student Bala Sundaram ’06 are working to decrease the size of the duplexer to less than a millimeter so it can be used in devices as small as cell phones. Once the size is decreased, the chip will be tested in Bradley’s advanced microwave engineering laboratory.

“Once it is made, we can work on manufacturing it on a large scale or licensing the technology to somebody,” Shastry said. Very soon, he will meet with university officials to discuss licensing the patent.

Shastry first began working in the area of distributed amplifiers (on whose principles the design of an active duplexer is based) at the University of Wisconsin-Madison in 1982. He continued to work in this area of research after joining Bradley in 1991. He collaborated with several Bradley seniors and graduate students during the next 15 years, developing different versions of the active duplexer.

The patented version of the active duplexer was developed in collaboration with Sundaram as part of his graduate capstone project.

“The collaboration between faculty and students – which is a hallmark of Bradley – has resulted in this,” Shastry said.

By 2005, he had presented the invention at the renowned international microwave conference in Europe and had the idea accepted for publication in the prestigious IEEE Microwave Theory and Techniques journal.

“We thought that since it was highly praised at the conference and accepted into such a prestigious journal that there would be some commercial value to this, as well,” Shastry said.

Bradley officials and their legal counsel agreed. 

Shastry notified university administrators that he was interested in seeking a patent in November 2005. By April 2007, he had submitted his application for the final patent. He was officially notified of its acceptance in August 2009.

Shastry uses the patent application experience when discussing intellectual property and its protection with his class. He impresses upon them the importance of documenting all their work and new ideas, and having a colleague attest to it in case a dispute ever arises over credit to the invention. He also learned that it takes a lot of effort, time and support from an organization to obtain a patent

“This requires a lot of institutional support,” he said. “It requires financial and legal support.”



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