IMEC reports 40 microwatt from micromachined piezoelectric energy harvester

Jun 21, 2007
IMEC reports 40 microwatt from micromachined piezoelectric energy harvester
Top view of micro-machined piezoelectric converters (before wafer bonding) realized by IMEC. Credit: IMEC

IMEC has fabricated an energy harvester to generate energy from mechanical vibrations by using micromachining technology. The harvester comes together with a model which can be used to optimize the device during design. Output powers up to 40µW were obtained which are in range of the required power for wireless sensor applications.

Energy harvesters, transforming ambient energy into electrical energy, are of great value for situations in which batteries cannot be replaced easily. A typical example is autonomous sensor networks that are spread over large areas or placed in locations that are difficult to access.

Vibration harvesters in general make use of electromagnetic, electrostatic or piezoelectric conversion to generate electrical power. IMEC developed, modeled and characterized a miniaturized vibration harvester based on a piezoelectric transducer.

For an input vibration with a resonance frequency of 1.8kHz and an amplitude of 180nm, a maximum experimental output power of 40µW was measured. This comes well in range of the amounts of power needed by wireless sensor applications, such as the pulse-oxymeter developed earlier by IMEC and IMEC-NL, operating from the Holst Centre in Eindhoven (The Netherlands).

"After the demonstration of a battery-less pulse-oxymeter, which is fully powered by a thermal scavenger, this is another encouraging result which brings us closer to seeing miniaturized scavengers in real-life applications. We believe that first of such devices will see market introduction in 5 years from now and will become mainstream by the end of next decade;" said Bert Gyselinckx, Program Director IMEC-NL in the Holst Centre.

The device consists of a piezoelectric capacitor formed by a Pt electrode, a PZT layer and a top Al electrode. This capacitor is fabricated on a cantilever that supports a mass on its tip. As the harvester is subjected to oscillations, the mass causes the piezoelectric layer to be stretched. By doing so, it induces an electrical power when an electrical load is connected to the device.

To optimize the proposed device concept, a model was generated to estimate the output power for a given design. The output power of the fabricated devices can be maximized by maximizing the quality factor Q (through a low parasitic dissipation) and the coupling between the electrical and mechanical part (GEMC; generalized electromechanical coupling factor).

Source: IMEC

Explore further: Cheap, environmentally friendly solar cells are produced by minimizing disruptive surface layers

add to favorites email to friend print save as pdf

Related Stories

Korean tech start-ups offer life beyond Samsung

Feb 23, 2015

As an engineering major at Seoul's Yonsei University, Yoon Ja-Young was perfectly poised to follow the secure, lucrative and socially prized career path long-favoured by South Korea's elite graduates.

Fresh nuclear leak detected at Fukushima plant

Feb 22, 2015

Sensors at the Fukushima nuclear plant have detected a fresh leak of highly radioactive water to the sea, the plant's operator announced Sunday, highlighting difficulties in decommissioning the crippled plant.

Spacewalking astronauts route cable in 1st of 3 jobs

Feb 22, 2015

(AP)—Spacewalking astronauts routed more than 300 feet (90 meters) of cable outside the International Space Station on Saturday, tricky and tiring advance work for the arrival of new American-made crew ...

Recommended for you

User comments : 0

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.