The conventional flexural plate-wave (FPW) device has advantages of high mass sensitivity, low phase velocity and low operation frequency. However, conventional FPW devices usually present a high insertion loss and low fabrication yield. This thesis aimed to reduce the insertion loss of conventional FPW devices. The influences of geometry of inter-digital transducers (IDTs), pair number of IDTs, depth of focus and length of delay line on the insertion loss of FPW device are investigated.
This research utilizes bulk micromachining technique to develop a low insertion-loss FPW device and the main fabrication steps include seven thin-film deposition and four photolithography processes. As the wavelength is 100 £gm, pair number of IDTs is 20, depth of focus is 1000 £gm and length of delay line is 500 £gm, the measured insertion loss of the implemented FPW device with conventional parallel-type IDTs and novel focus-type IDTs are equal to -48 dB and -45.06 dB, respectively. On the other hand, the insertion loss of FPW device with focus-type 25-pairs IDTs (-43.69 dB) is smaller than that of FPW device with focus-type 20-pairs IDTs (-45.06 dB). Additional, the measured insertion loss of FPW device with 500 £gm focus depth (-41.47 dB) is smaller than that of FPW devices with 1000 £gm focus depth (-43.69 dB) or with 1500 £gm focus depth (-45.39 dB). Furthermore, the FPW device with 500 £gm delay line presents a smaller insertion loss (-40.46 dB) than that of FPW devices with 250 £gm delay line (-41.47 dB) or with 750 £gm delay line (-40.95 dB).
Finally, under the optimized specifications (focus-type/25 pairs IDTs, 500 £gm focus depth and 500 £gm delay line), the FPW-based microsensor demonstrates a high sensitivity (91.53 cm2/g), high sensing linearity (99.18 %) and low insertion loss (-40.46 dB), hence it is very suitable for development of biomedical sensing microsystem.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0731112-123300 |
| Date | 31 July 2012 |
| Creators | Lin, Ji-Yuan |
| Contributors | Wei-Leun Fang, Ruey-Shing Huang, I-Yu Huang, Yu-Cheng Lin |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0731112-123300 |
| Rights | user_define, Copyright information available at source archive |
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