Tiny MEMS Devices Filter, Amplify Electronic Signals

Researchers are developing a new class of tiny mechanical devices containing vibrating, hair-thin structures that could be used to filter electronic signals . A tiny prototype, roughly comparable in size to a grain of sand, is pictured above. Image courtesy of Birck Nanotechnology Center, Purdue University

Researchers at Duke University are developing a new class of tiny mechanical devices containing vibrating, hair-thin structures that could be used to filter electronic signals for a variety of applications. Because the devices, called resonators, vibrate in specific patterns, they are able to cancel out signals having certain frequencies and allow others to pass. The result is a new type of “band-pass” filter, a component commonly used in electronics to permit some signals to pass while blocking others, says Jeffrey Rhoads, an assistant professor of mechanical engineering at Purdue University.

Such filters are used in portable electronics, where they allow devices to process signals with minimal interference and maximum transmission efficiency. The new technology represents a potential way to further miniaturise band-pass filters while improving their performance and reducing power use, Rhoads says.

The device is an example of a microelectromechanical system, or a MEMS, which contain tiny moving parts. Incoming signals generate voltage that produces an electrostatic force, causing the MEMS filters to vibrate.

Some researchers have proposed linking tiny beams in straight chains, but Rhoads has pursued a different approach, arranging the structures in rings and other shapes, or “non-traditional coupling arrangements.” One prototype, which resembles spokes attached to a wheel’s hub, is about 160 µm in diameter, or roughly the same size as a grain of sand.

Such resonators could be used for advanced chemical and biological sensors in medical and defense applications  and possibly for a new type of “mechanical memory element” that harnesses vibration patterns to store information.

More information on the research is available from the Duke University News web site.

Tags: band-pass, Duke University, Electronics, Jeffrey Rhoads, MEMS, microelectromechanical system