This document describes the design, fabrication, and testing of an ultrasonic energy harvester using MEMS technology. It uses a 2 degree-of-freedom motion mechanism in the MEMS chip to harvest vibration energy from two orthogonal directions. The MEMS chip is paired with an ultrasonic transducer that transmits ultrasonic waves to the chip. Experimental results show the device is able to charge a capacitor up to 21.4 nanowatts of power. The MEMS harvester provides advantages over piezoelectric cantilever harvesters such as smaller size, better sensitivity, and lower cost. Potential applications include powering implantable biomedical sensors.

2. Guided by, Done by,
Muhzina M H LIJINRAJ.T.V

3. CONTENTS
 INTRODUCTION
 DESIGN
 FABRICATION
 EXPERIMENTAL RESULTS
 CONCLUSION
 REFERENCES

4. INTRODUCTION
 NEED OF ENERGY HARVESTERS
 EXISTING HARVESTERS
 DRAWBACKS

5. ULTRASONIC ENERGY
HARVESTER
TWO METHODS.
 USING MEMS.
 USING PIEZOELECTRIC
CANTILEVER.

6. ULTRASONIC ENERGY
HARVESTER USING MEMS
 ULTRA SONIC
TRANSDUCERS
 MEMS CHIP
 STORAGE
DEVICES

7. BLOCK DIAGRAM

8. ULTRASONIC
TRANSDUCER
 A SQ -40T ULTRASONIC
TRANSDUCER WAS
USED.
 IT TRANSMITS
ULTRASONIC WAVES.
 IT HAS A RESONANCE
FREQUENCY OF 40 KHZ.
 DRIVEN BY A 10Vpp AC
SIGNAL.

9. MEMS
 MEMS(Micro Electro Mechanical
System).
 CONSISTS OF MICRO ACTUATORS
MICRO SENSORS,MICROELECTRONICS
 SIZE IS IN µm RANGE.

10. DESIGN
 A 2 DOF MOTION
MECHANISM .
 VIBRATION ENERGY.
 SEISMIC MASS MOVES.
 CHANGES THE
CAPACITANCE OF THE
X&Y FRAMES.
 CONITRIBUTE THE
CHARGING OF THE
LOAD.
3-D VIEW OF MEMS MECHANISM

11. MOTION MECHANISM TO
HARVEST VIBRATION
ENERGY TO A PLANE

12.  TWO MODES.
 TWO RESONANCE FREQUENCIES.
 MECHANICAL COUPLING IN THE COMBS FROM ONE
MODE TO ANOTHER IS LESS THAN 2%.
 VIBRATION IN Z-DIRECTION CAN BE IGNORED.
 RESONANCE FREQUENCY DEPENDS ON THE
STIFFNESS OF THE BEAMS AND MASS,

13. MECHANICAL
STRUCTURE DESIGN
SHOWING THE
MOVEMENT ALONG
THE X-AXIS

14. MECHANICAL
STRUCTURE DESIGN
SHOWING THE
MOVEMENT ALONG
THE
Y-AXIS

15. DESIGN PARAMETERS FOR 2-DOF ENERGY
HARVESTER

16. FABRICATION
MEMS FOUNDRY PROCESS
 SURFACE METALPADS ARE DRIE IS PERFORMED FROM
PATTERNED FOR OHMIC CONTACT THE FRONT SIDE OF THE WAFER

17.  A PROTECTIVE POLYMIDE  A DEEP TRENCH UNDERNEATH
LAYER IS APPLIED TO THE THE MOVABLE STRUCTURES
FRONT SIDE IS CREATED

18.  THE EXPOSED BURIED OXIDE  THE POLYMIDE COAT
IS REMOVED USING A WET HF IS REMOVED BY OXYGEN
ETCH PLASMA

19. SEM IMAGE OF THE PHOTOGRAPH OF THE
FABRICATED ENERGY PACKAGED DEVICE
HARVESTER

20. ENERGY HARVESTING CIRCUIT DIAGRAM

21.  ULTRASONIC ENERGY IS CONVERTED INTO
ELECTRICAL ENERGY.
 A RECTIFYING CIRCUIT IS USED.
 DIODES (1N5711).
 CAPACITOR CHARGED(1µF).

22. ULTRASONIC TRANSDUCER & PACKAGED MEMS CHIP

23. MAGNITUDE CURVES OF THE OUTPUT VOLTAGE
V/S FREQUENCY

24. COMPARISON BETWEEN EXPERIMENTAL RESULTS
&STIMULATION
RESULTS

25. USING PIEZOELECTRIC
CANTILEVER

26. MEMS V/S PIEZOELECTRIC
CANTILEVER

27. ADVANTAGES
 SMALL SIZE.
 BETTER SENSITIVITY.
 COST EFFECTIVE.
 LESS HARM TO PATIENT.

28. APPLICATIONS
 A BETTER APPLICATION IS IN POWERING THE
IMPLANTABLE BIOSENSORS.

29. CONCLUSION
 THESE CAN EXTRACT ULTRASONIC ENERGY FROM
ALL DIRECTIONS IN THE DEVICE PLANE.
 INCREASES EFFICIENCY OF THE ENERGY
SCAVENGING.
 A POWER LEVEL OF 21.4nw CAN BE OBTAINED.
 BETTER SENSITIVITY.

30. REFERENCES
 Yong Zhu, S. O. Reza Moheimani, Mehmet Rasit Yuce, “A 2-DOF
MEMS Ultrasonic Energy Harvester”, IEEE SENSORS JOURNAL,
VOL. 11, NO. 1, JANUARY 2011
 WWW.WIKIPEDIA .COM

31. THANKS

32. QUERIES???