• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.7A
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• pp.669-681
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• 2010

In this paper, we analyze the active RFID system ISO/IEC 18000-7. In order to apply to USN, which consists active RFID tags and sensor nodes, we propose UWB-based Class 4 active RFID protocol using active RFID relay tag as relay AP. To compare the performance between the existing ISO/IEC 18000-7 system and the proposed system, we introduce sensitivity-based measurement of achieved coverage and system efficiency. Also, we analyze the performance of the proposed system and compare it with that of the existing system through MCL analysis and SLS analysis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.8
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• pp.1430-1435
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• 2007

We developed a 440MHz surface acoustic wave (SAW) microsensor integrated with pressure-temperature sensors and ID tag. Two piezoelectric substrates were bonded, in which ${\sim}150\;{\mu}m$ cavity was structured. Four sides were completely sealed by JSR photoresist (PR). Pressure sensor was placed on the top substrate, whereas ill tag and temperature sensor were placed on the bottom substrate. Using network analyzer, the developed microsensor was wirelessly tested. Sharp reflection peaks with high S/N ratio, small signal attenuation, and small spurious peaks were observed. All the reflection peaks were well matched with the coupling of mode (COM) simulation results. With a 10mW RF power from the network analyzer, a ${\sim}1$ meter readout distance was observed. Eight sharp ON reflection peaks were observed for ID tag. Temperature sensor was characterized from $20^{\circ}C$ to $200^{\circ}C$. A large phase shift per unit temperature change was observed. The evaluated sensitivity was ${\sim}10^{\circ}/^{\circ}C$.