MEMS 2003 and Beyond

1. (Slide)

2. Before we discuss the future of MEMS, maybe we'd better establish what we are 
considering MEMS to be.  MEMS are "Microelectromechanical Systems" and there are 
seven criteria we can use to identify if something really is MEMS.  Three of the seven are 
on this page.

3. On this page are the remaining four criteria of what MEMS are.  The last point is 
important:  Many successful MEMS applications involve using MEMS not as "brute force" 
devices, but as devices placed at some critical place so they may, with minimal effort, 
control flux of some kind.  The rough analogy is a transistor.  It does not generate the 
current source, but it does allow you to control current.  Add one electron on the gate and 
100,000 come out the emitter!

4. In this slide are shown a number of Defense applications of MEMS.

5. So where is MEMS going?  What is the future?  Here are some "blue-sky" visions of 
where MEMS might take us in the year 2003.  Will these visions be completely realized by 
then?  Probably not, but these are reasonable goals.

6. Here I show a typical radio transceiver; note that most of the components are off-chip, 
passive, discrete devices.  MEMS devices, such as the one shown on this slide, can replace 
the discrete components needed for the filters.  Since the MEMS components can be 
integrated with the transistor electronics, MEMS has reduced the total parts count, the total 
size, and the total cost of the radio. 

7. If we limit ourselves to lower frequencies (10 kHz, for example) we can set up more 
complex MEMS filters, such as this sixth-order bandpass filter fabricated at the University 
of Michigan.

8. MEMS have a role to play in macro technology, and in this slide I show how jet engines 
may be made more robust via miniature sensors and actuators.  It is possible to do 
lithography on 3-D surfaces (upper left); possible to adjust heat conductivity (middle left); 
and even to resolve strain to very low levels (less than 0.1 microstrain).  Candidate sites on 
jet engines for MEMS are shown on the right.

9. At the lower right is an exploded view of a MEMS extensiometer, capable of reading 
absolute strain with no drift.  With a gage length of 1mm (millimeter) this device can 
resolve strains to help with condition-based maintenance and structural health and 
monitoring.

10. At the lower right is an exploded view of a MEMS extensiometer, capable of reading 
absolute strain with no drift.  With a gage length of 1mm (millimeter) this device can 
resolve strains to help with condition-based maintenance and structural health and 
monitoring.

11. Here is a vision of how MEMS might be used in a "pressure belt" that is applied to an 
airplane wing.  This belt would allow the measurement of normal pressure on the wing 
during test flights.

12. One exciting use of MEMS is to make specialized, electronically programmable 
diffraction gratings.  These gratings will allow a soldier to "see" light only in specific 
wavelenghts.  And this can be done at great stand-off distances, assuming the wavelengths 
of interest are not absorbed by the atmosphere.  This is shown on the upper right.

If the gratings can be programmed to admit light with a certain distribution of energy across 
the various wavelenghts, then the grating can be programmed to "see" only various 
chemical compounds.  The operation of the gratings is shown on the right, where the 
polychromator is shown admitting only a certain spectra of light.  This is shown on the left 
and center.

Thus, the soldier may be able to "look" specifically for various chemical agents of interest.

Again, the key to accomplishing this is the use of MEMS technology to make an 
electrically-controlled diffraction grating.

13. If we let our imagination run a bit further, we might conceive of the system as a 
dandelion seed, approximately 4mm (millimeters) in diameter.

14. Have we any chance of actually doing it?  I show here an existance proof that micro 
hexagonal-cell, honeycomb-core, composite material can be fabricated.  The hexagonal 
cells are as small as 25 ?m across the flats.  Further, they actually wick fuel, and so provide 
pump-less fuel delivery system for combustion-based energy generation.

15. We can make intricate MEMS at the mosquito-size scale.  Note that comparisons 
between the proboscis of the mosquito and the MEMS needles!

16. And if we need the fuel atomized, we can even use a low-power MEMS approach to 
making 25 ?m diameter droplets.

17. So, I close by saying that MEMS, between now and 2003, can make possible "wrist" 
communications, robust jet engines, and micro airborne sensor/communicator platforms.

Thank you for your time and attention.