New gas sensor chip paves the way to autonomous e-nose

Jun 09, 2010
Closely-packed array of individually vibrated microbridge resonators can be used for separation of gases upon application of specific coatings.

Imec and Holst Centre researchers have developed very sensitive integrated sensing elements for gas detection. The polymer-coated microbridges in high-density arrays can detect ppm-level concentrations of vapors using on-chip integrated read-out techniques. The demonstrated technology is very suitable for miniaturization of electronic nose devices thanks to the low power consumption (<1 µW/bridge) and small form factor.

Wireless sensor nodes that can chemically detect gaseous compounds are rapidly gaining interest from markets such as food monitoring, healthcare and safety. One of the main gas sensing approaches in uncontrolled environments is the identification of vapors (“smells”) using multiple sensing elements (“receptors”), in a system that is often referred to as an “” or “e-nose”. An accurate e-nose requires small, integrated, low-power detectors with individually tuned chemical coatings. Current solutions, like chemi-resistors or quartz crystals are however not scalable or power-efficient enough to build low-power small form factor e-noses.

Imec and Holst Centre have developed a new generation of microbridges with embedded individual piezoelectric “shakers” in a high-density array with very high fabrication yield. The novel design allows for rapid coating of a range of absorbents on individual microbridges using commercial inkjet printing technology. The suspended structures vibrate individually, and changes in their modes of vibration (resonances) are monitored as an indication of vapor absorption in their coatings. Due to the very high length-to-thickness ratio of the microbridges, imec and Holst Centre’s novel gas has a high sensitivity to low-concentration vapors. Moreover, by implementing integrated piezoelectric read-out schemes, ultra-low power operation could be demonstrated.

The scanning electron microscope image of a complete sensor chip (9mm x 9mm) consisting of 160 unique individually addressable micromechanical resonators, with aspect ratios (length/thickness) ranging from 140-1,500.

Current work is ongoing to integrate the structures with low-power analog read-out circuits and to demonstrate simultaneous measurements from multiple structures. This truly low-power miniaturized implementation of an e-nose technology can be used in current applications such as wine and cheese monitoring, but could in the future also help sniff-out human conditions such as asthma, lung cancer, and kidney diseases.

Explore further: Apple helps iTunes users delete free U2 album

add to favorites email to friend print save as pdf

Related Stories

Wireless EEG system self-powered by body heat and light

Apr 09, 2008

In the framework of Holst Centre, IMEC has developed a battery-free wireless 2-channel EEG (electroencephalography or monitoring of brain waves) system powered by a hybrid power supply using body heat and ...

Imec achieves breakthrough in battery-less radios

Feb 09, 2010

At today's International Solid State Circuit Conference, Imec and Holst Centre report a 2.4GHz/915MHz wake-up receiver which consumes only 51µW power. This record low power achievement opens the door to battery-less ...

New concept for bendable packaged ultra-thin chips presented

Apr 04, 2006

IMEC and its associated laboratory INTEC of the University of Ghent jointly developed a new process flow for ultra-thin chip packages resulting in bendable packaged chips of only 50µm thickness. The technology enables embedding ...

Recommended for you

Apple helps iTunes users delete free U2 album

3 hours ago

Apple on Monday began helping people boot U2 off their iTunes accounts after a cacophony of complaints about not wanting the automatically downloaded free album by the Irish rock band.

User comments : 0