2.45GHz Surface Acoustic Wave RFID device
| Autor: | Bing-Yu Wang, 王炳昱 |
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| Rok vydání: | 2012 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 100 Currently, surface acoustic radio frequency identification (SAW RFID) tag received increasing attention because of several advantages such as large reliable reading range, low power consumptions, able to operate high temperature range from -40C to 400C and able to be used in harsh environment. One pair of metallic interdigital transducers (IDT) and several reflectors are on the surface of SAW tags. When an electrical signal is applied to IDT, a mechanical acoustic wave will be triggered and transferred to reflector. The time-dependent reflection waves return to IDT, and mechanical waves retransform to AC signals through direct piezoelectric effect. When different patterns of AC signals are measured and recorded, different individual tags will be identified. For SAW RFID tags, the central frequency and number of possible codes are two of most important parameters. In this study, SAW RFID device were operated in high harmonic modes at 2.45GHz. Moreover, encoding scheme was studied to increase the information capacity of SAW tags. In this thesis, the 2.45GHz center frequency of Surface Acoustic Waves Radio Frequency Identification (SAW RFID) tag was developed. The substrate of SAW RFID was 128°Y-X cut Lithium Niobate (LiNbO3) piezoelectric substrate. The width of the IDT and reflectors were designed as 400nm to achieve center frequency of SAW tag as 2.45 GHz. The time position encoding and phase encoding were used to enhance the information capacity of SAW tags. The IDT and reflectors were deposited on the LiNbO3 piezoelectric substrate successfully by E-beam lithography and lift-off technique. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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