Sensors for the real world

November 5, 2012

Over the last decade there has been an increased interest in developing resonators for gravitmetric sensing; however, the sensors' response to variations in temperature has prevented them from being used outside the laboratory. New sensors developed by researchers at the University of Cambridge negate the effects of temperature so that they may be used in industries including health care, telecommunications and environmental monitoring.

Sensors built from bulk acoustic wave (BAW) consist of a piezoelectric layer sandwiched between two , to which a variable frequency signal is applied. The resonator vibrates at a given frequency, and the properties of the resulting acoustic wave allow researchers to determine what is occurring in the environment.

The main application of these nanoscale sensors is to measure a mass load. By tracking changes in the acoustic wave, mass changes on the sensors can be detected. The resonators can be altered to detect a number of different things, from antigens/ to environmental contaminants.

The major issue which has prevented the adoption of these resonators in commercial sensing applications has been their unwanted response to . When the temperature changes, the acoustic wave changes along with it, so it is impossible to determine whether the change has been motivated by something the resonator is trying to detect or a change in temperature. For this reason, the use of these resonators has been limited to laboratories where can be tightly controlled.

Many researchers have attempted to compensate for the effects of temperature, but as these effects are non-linear, they can only be minimised, not eliminated completely. Now, researchers from the Department of Engineering have designed a thin film bulk resonator that allows simultaneous measurement of temperature and mass loading in a single device. The resonator has been designed so that it has two resonances which react differently to mass and temperature changes.

"This has two consequences," says Dr Luis Garcia-Gancedo, a member of Dr Andrew Flewitt's group in the Department of Engineering. "First, we are able to eliminate the effects of temperature completely regardless of its non-linearity. Secondly, we are able to measure mass and temperature with extremely high sensitivity at exactly the same location, which we haven't been able to do before."

With the assistance of Cambridge Enterprise, the team is looking at two primary applications for the resonators: biological systems and physical sensing. The resonators could be used for applications such as detecting viruses in a health care setting, or contaminants in drinking water. Other potential applications include air quality or pressure monitoring.

The resonator is able to detect masses to the order of 10-15 grams, which is approximately the size of one virus. The size of the resonator (typically a few micrometres square) means that they can easily be embedded in various devices.

"One of the problems with existing sensing technology is that if you're trying to measure two different physical properties, the are often based on two different mechanisms," says Dr Garcia-Gancedo. "The integration of two different sensing mechanisms means that you often end up with a bulky item. But what we have developed uses exactly the same technology with exactly the same electronics, without any increase in size."

Explore further: Exotic behavior when mechanical devices reach the nanoscale

Related Stories

Exotic behavior when mechanical devices reach the nanoscale

May 15, 2011

Most mechanical resonators damp (slow down) in a well-understood linear manner, but ground-breaking work by Prof. Adrian Bachtold and his research group at the Catalan Institute of Nanotechnology has shown that resonators ...

Polymer's hunt for nicotine

August 4, 2011

Newly synthesized polymer, fitted with molecular pincers of carefully tailored structure, effectively captures nicotine molecules and its analogues. The polymer can be used for fabrication of sensitive and selective chemical ...

First nanoscale mass spectrometer created

July 22, 2009

Using devices millionths of a meter in size, physicists at the California Institute of Technology (Caltech) have developed a technique to determine the mass of a single molecule, in real time.

Recommended for you

Android's Nougat update isn't flashy, but still pretty handy

September 28, 2016

Nougat, Google's latest update of its Android smartphone software, isn't particularly flashy; you might not even notice what's different about it at first. But it offers a number of practical time-saving features, plus a ...

Disabled man gets license, shows driverless tech's potential

September 28, 2016

Former Indy Racing League driver Sam Schmidt has done a lot in the 16 years since an accident left him paralyzed from the neck down. He runs a racing team and a foundation. He's raced a sailboat using his chin. But the man ...

Hyperloop pushes dream of low-cost futuristic transport

September 23, 2016

Is it a plane, is it a train? No, say supporters of Hyperloop, a futuristic mode of transport floated by Silicon Valley billionaire Elon Musk that promises high-tech, high-speed and cheap travel over long distances.

MIT's flea market specializes in rare, obscure electronics

September 25, 2016

Once a month in the summer, a small parking lot on the Massachusetts Institute of Technology's campus transforms into a high-tech flea market known for its outlandish offerings. Tables overflow with antique radio equipment, ...

First test of driverless minibus in Paris Saturday

September 24, 2016

The French capital's transport authority will on Saturday carry out its first test of a driverless minibus, in the hope that regular routes for the hi-tech vehicles will be up and running within two years.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

AceLepage
5 / 5 (2) Nov 05, 2012
"...10-15 grams, which is approximately the size of one virus"

A macro virus if I have ever seen one :)

(I understand that this must have meant to read 10 to the power of -15)

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.