DIGITALLY-TUNABLE MEMS FILTER USING MECHANICALLY-COUPLED

RESONATOR ARRAY

Hengky Chandrahalim and Sunil A. BhaveOxideMEMS Lab, Electrical and Computer Engineering, Cornell University, Ithaca,

New York, USA

Advisor ： Cheng-Hsien Liu

Reporter : Ming-Yen Chen

Date ： 2008/6/11

Outline

Abstract Introduction Background Experimental setup Experimental results Conclusion

Abstract

Digital tuning Resonator array Band-select filter

Introduction-1

Why band-select filter？

Hz

Introduction-2

Extensional mode resonator

Background-1

S.A. Bhave, and R.T. Howe, “Silicon nitride-on-silicon bar resonator using internal electrostatic transduction,” Transducers’05, Seoul, Korea, June 5-9, 2005, pp. 2139-2142.

100nm SiN

3um SOI

Poly electrode

Background-2

f = (n/2L) (E/ρ)^1/2

E ： effective elastic modulus for 2D expansion

ρ: density of the resonator respectively

n ： harmonic order

Center frequency : 511 MHz

Experimental setup

1. DC1=DC4=+Vp, DC2=DC3=OFF

2. DC1=DC3=+Vp, DC2=DC4=-Vp

3. DC1=DC2=DC3=DC4=+Vp

Experimental results-1

1. DC1=DC4=50V, DC2=DC3=OFF

4-port filter

Experimental results-2

2. DC1=DC3=40V, DC2=DC4= -40V

resonator 1 and 2 : Out of plane

Lower sub-band filter

Experimental results-3

3. DC1=DC2=DC3=DC4= 40V

resonator 1 and 2 : in plane

higher sub-band filter

Experimental results-4

Conclusion

1. Digital tuning at 509 MHz with 1.4 MHz bandwidth and with sub-bands 700 kHz wide.

2. More resonators will provide finer

sub-bands.

Thanks for Your Attention!