1. DIGITALLY-TUNABLE MEMS FILTER USING MECHANICALLY-COUPLED RESONATOR ARRAY Hengky Chandrahalim and Sunil A. Bhave OxideMEMS Lab, Electrical and Computer Engineering, Cornell University, Ithaca, New York, USA Advisor ： Cheng-Hsien Liu Reporter : Ming-Yen Chen Date ： 2008/6/11

2. Outline Abstract Introduction Background Experimental setup Experimental results Conclusion

3. Abstract Digital tuning Resonator array Band-select filter

4. Introduction-1 Why band-select filter ？ Hz

5. Introduction-2 Extensional mode resonator

6. 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

7. 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

8. Experimental setup 1.DC1=DC4=+Vp, DC2=DC3=OFF 2.DC1=DC3=+Vp, DC2=DC4=-Vp 3.DC1=DC2=DC3=DC4=+Vp

9. Experimental results-1 1. DC1=DC4=50V, DC2=DC3=OFF 4-port filter

10. Experimental results-2 2. DC1=DC3=40V, DC2=DC4= -40V resonator 1 and 2 : Out of plane Lower sub-band filter

11. Experimental results-3 3. DC1=DC2=DC3=DC4= 40V resonator 1 and 2 : in plane higher sub-band filter

12. Experimental results-4

13. 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.

14. Thanks for Your Attention!