Implant that moves, electric shoes at ISSCC

Rick Merritt

November 21, 2011

Rick Merritt

SAN JOSE – A tiny implant that can propel itself through your body. A tennis shoe that can gather enough energy from walking to power a pedometer. These battery-free devices are two of dozens of designs etched in silicon likely to capture the imagination at the International Solid-State Circuits Conference in February.

Engineers from Asia will present more papers (38) than those from the U.S. (33) or Europe (29) for the first time at ISSCC in 2012. U.S. engineers typically present the majority of papers at the San Francisco event. Last year they gave 36 papers compared to 34 and 30 for Asia and Europe respectively.

Korea was almost single handedly the reason for Asia's rise in 2012, said Kenneth Smith, an ISSCC organizer and professor at the University of Toronto. In 2012, ISSCC staff accepted 30 Korean papers, up from 20 a year ago. The country's well-funded national research center, KAIST, was author of many of the papers.

Meanwhile, Japan submitted fewer papers, in part due to the impact of the March earthquake and tsunami. China actually submitted twice as many papers for the 2012 event (34) than it did a year ago, but it had half as many accepted just two, down from four in 2011.

One of the most novel papers at ISSCC this year describes a chip that can act as a self-propelling medical implant. The 0.6mm² device can move through fluid in a controlled manner at half a centimeter per second thanks to a 1.8 GHz wireless signal that delivers 500 microwatts to a 65nm receiver.

"The ISSCC paper describes the chip we designed and taped out to demonstrate our propulsion methods on a wireless prototype," said Dan Pivonka, one of two Stanford doctoral candidates who created the device.

The chip uses two propulsion methods described in earlier papers Pivonka co-authored with Stanford professor Teresa Meng, a wireless pioneer who co-found Wi-Fi vendor Atheros. Both propulsions methods "are based on electromagnetic forces that flowing currents experience in a magnetic field," said Pivonka in an email exchange.

A simulation from one of those earlier papers is shown above right.

"The device is capable of controllable motion in any fluid medium, making it very versatile for biomedical applications," he said. "We've been working with the medical community, and so far the primary uses are likely to be precision drug delivery, sensing or imaging for diagnostic purposes, or use as a surgical aid," he added.