MESA+ University of Twente
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Nima Izadi (promotion date: 7 January 2011)

Bio-inspired MEMS aquatic flow sensor arrays

Promotion date: 7. January 2011

Promotor: Prof. dr. ir Gijs Krijnen

In this thesis, for the first time, design and fabrication of aquatic flow sensors with capacitive readout using MEMS technology, has been shown. The design of the flow sensors is based on the function of sensory organs of the lateral line of fish. These sensory organs are very sensitive and robust. That is what we aimed to achieve by mimicking them.

Three different designs are proposed. Fabrication schemes are detailed and optimized procedures have been devised. At the end one of the concepts has been tested to demonstrate the credibility of the concept.

You did open some new research field!

Yes, more or less so! The Transducers Science and Technology group once started research to build a capacitive sensor usable in the air, by looking at crickets. My task was to search for possibilities for such a sensor, but usable in water. As you know, water is a very troublesome medium for performing electronic measurements within.

I looked at feasible principles that could be derived from the fish lateral line, to come to a design for a capacitive sensor at the end. I have proposed and fabricated three different designs and performed measurements to show the technology actually did work.

Was there an important moment during your thesis project?

I had some nice results during the project but the sensors did not work until the last moment. The last batch of sensors I fabricated was the most important one to me. Especially when I got the signal coming out of the sensors when performing real measurements. I mean, that working on them for four years, starting from scratch, was worth all the effort. It shows that the design of capacitive sensors for an aquatic medium works in principle. Right now, I am working to write some papers out of the results of the measurements. That’s very rewarding; I like to finish the job properly.

Were some articles published along the way also?

An article was published in the Journal of Micromechanics and Microengineering (JMM) and has been chosen as one of the highlights of 2010. I also have presented my results at several conferences including the Transducer conference in 2009 at the United States, which is an important one in my field.

How did you develop, as a researcher and scientist?

I learned to look at the overall problem more critically, taking all its aspects into account. My supervisor Gijs Krijnen was a very good model for me on this aspect during the project and I have learned many things from him. I had lots of contacts with other project partners and MESA+ members, be it cleanroom experts, fellow PhD’s and also members from other groups.

What are your future plans?

I now work for Sensata Technologies in Almelo, formerly known as Texas Instruments. I am a member of the MEMS group, developing and designing pressure sensors for the automobile industry. I enjoy to see all aspects of a new product coming together and see it performing under practical conditions. This I did miss in academic research. I like to see things at work!

What, in your opinion is important for Mesa+ to stay successful in the future?

Increasing the collaborations between groups more, would be very advantageous. For example, if one experiences a lack of knowledge in his own group, it is helpful if a lot of contacts exist. Finding who has the specific knowledge within Mesa+ is not always an easy job to do. Also in many practical issues knowing one’s expertises better, can be of immediate use. So, I guess, it is a good thing to formulate more collaborative projects between groups.

Also, I find, Mesa+ can be more practical, making good use of spin-off research, products and companies. More attention and promotion of the activities in different media will be helpful, I am convinced.