| Presentation | 2003/9/22 Unidirectional Interdigital Transducers and Resonators Using Grating SAW Substrates and Application to Low Loss Wide Band Filters Kazuhiko Yamanouchi, Yusuke Satoh, |
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| Abstract(in Japanese) | (See Japanese page) |
| Abstract(in English) | Surface acoustic wave (SAW) filters employing the conventional interdigital transducer (IDT) show inherent minimum insertion loss of 6 dB, because of bidirectionality and strong passband ripple due to triple-transit echo and secondary effects. In order to avoid these flaws, many types of unidirectional interdigital transducers are proposed.These unidirectional transducers have small transducer efficiency. Therefore it is difficult to obtain wide band and low loss filters. In this paper we describe a new sinle phase unidirectional transducer (UDT) with about λ/4 electrode width, because the inerdigital transducers with λ/4 electrode width have good transducer efficiency. The new UDTs are fabricated on the very thin dielectric grating and the very shallow groove SAW substrates. The electromechanical couplings (k^2) of electrodes on thin dielectric gratings are drastically decreased. The k^2 of the electrodes on SiO_2 laysers of thickness of H/λ=0.01 using LiNbO_3 SAW substrates is about (1/2) k^2. Therefore the thickness of SiO_2 is about 0.4μm and 0.04μm at the center frequency of about 100MHz and 1GHz devices, respectively. Also the very thin grooves have a large reflection coefficients of SAW. The calculation results show wide band low loss filters with various k^2 materials. Also we show new SAW resonators using the admittance and suceptance changes. |
| Keyword(in Japanese) | (See Japanese page) |
| Keyword(in English) | surface acoustic wave / interdigital transducer / unidirectional transducer / low loss filter / SAW resonator |
| Paper # | US2003-49 |
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| Committee | US |
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| Conference Date | 2003/9/22(1days) |
| Place (in Japanese) | (See Japanese page) |
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| Topics (in Japanese) | (See Japanese page) |
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| Registration To | Ultrasonics (US) |
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| Language | JPN |
| Title (in Japanese) | (See Japanese page) |
| Sub Title (in Japanese) | (See Japanese page) |
| Title (in English) | Unidirectional Interdigital Transducers and Resonators Using Grating SAW Substrates and Application to Low Loss Wide Band Filters |
| Sub Title (in English) | |
| Keyword(1) | surface acoustic wave |
| Keyword(2) | interdigital transducer |
| Keyword(3) | unidirectional transducer |
| Keyword(4) | low loss filter |
| Keyword(5) | SAW resonator |
| 1st Author's Name | Kazuhiko Yamanouchi |
| 1st Author's Affiliation | Electronics Engineering, Tohoku Institute of Technology() |
| 2nd Author's Name | Yusuke Satoh |
| 2nd Author's Affiliation | Electronics Engineering, Tohoku Institute of Technology |
| Date | 2003/9/22 |
| Paper # | US2003-49 |
| Volume (vol) | vol.103 |
| Number (no) | 339 |
| Page | pp.pp.- |
| #Pages | 6 |
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