1 / 13

Teacher ： Cheng-Hsien Liu Reporter ： Chien Thanh Nguyen Date ： 2008.4.16

Temperature measurement and compensation based on two vibrating modes of a bulk acoustic mode microresonator. M.Koskenvuori 1 , V.Kaajakri 2 , T.Mattila and I. Tittonen 1 Micro and Nanosciences laboratory and Center for New Materials, Helsinki University of Technology,Finland

caraf
Download Presentation

Teacher ： Cheng-Hsien Liu Reporter ： Chien Thanh Nguyen Date ： 2008.4.16

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Temperature measurement and compensation based on two vibrating modes of a bulk acoustic mode microresonator • M.Koskenvuori1, V.Kaajakri2, T.Mattila and I. Tittonen1 • Micro and Nanosciences laboratory and Center for New Materials, Helsinki University of Technology,Finland • 2. VTT – Technical Research Center of Finland, Finland MEMS 2008, Tucson, AZ, USA, January 13-17, 2008 Teacher ： Cheng-Hsien LiuReporter：Chien Thanh Nguyen Date：2008.4.16 PME5230 Midterm Presentation

  2. Outline • Introduction • Device • Method • Measurement results • Discussion • Conclusion PME5230 Midterm Presentation

  3. Introduction Temperature induced drift MEMS resonator Material compensation SiO2, Al2O3 Compensated electronically PME5230 Midterm Presentation

  4. Device Fundamental mode of vibration Lame’ Mode Square-extension mode Single crystal silicon, square-extensional bulk-acoustic-mode resonator (SE-BAW) PME5230 Midterm Presentation

  5. Method Determine temperature coefficients of the frequency of two mode α1= ((df/f)/dT)lame= -22.3 ppm/K α2 = ((df/f)/dT)SE = -27.3 ppm/K PME5230 Midterm Presentation

  6. Method (1) (2) PME5230 Midterm Presentation

  7. Measurement Results • Experiment setup 1) Pt-100 sensor next to resonator chip 2) Resonator as a thermometer itself PME5230 Midterm Presentation

  8. PT-100: frequency error: 15ppm PT-100: compensation error df/f > 2 ppm Resonator thermometer: compensated df/f < 1 ppm PME5230 Midterm Presentation

  9. PME5230 Midterm Presentation

  10. Discussion Disadvantage: 1) A very accurate frequency measurement is needed 2) The beat frequency of the two modes is fairly high reducing the sensitivity 3) Any mixing products of the two excited modes will degenerate the reference oscillator noise performance PME5230 Midterm Presentation

  11. Conclusion • A resonator can be used as a thermometer by measuring the frequency change of the Lame- and SE- mode • Temperature induced frequency shift can be compensated to better • Provide a cost effective way to obtain crystal oscillator (TCXO) performance with inexpensive silicon resonator. PME5230 Midterm Presentation

  12. Thank you for your attention! PME5230 Midterm Presentation

  13. Reference CMOS-compatible dual-resonator MEMS temperature sensor with mili-degree accuracy C.M. Jha, G. BAhl, R. Melamud, S.A. Chandorkar, M.A. Hopcroft, B. Kim, M. Agarwwal, J. Salvia, H. Mehta and T.W. Keny (transducer 2007) PME5230 Midterm Presentation

More Related