• Journal of Electrical Engineering and Technology
• /
• v.13 no.1
• /
• pp.501-512
• /
• 2018

Radio frequency identification (RFID) sensor tag provides several advantages including battery-less operation and low cost, which are suitable for long-term monitoring. This paper presents a self-powered RFID temperature sensor tag for online temperature monitoring in substation. The proposed sensor tag is used to measure and process the temperature of high voltage equipments in substation, and then wireless deliver the data. The proposed temperature sensor employs a novel phased-locked loop (PLL)-based architecture and can convert the temperature sensor in frequency domain without a reference clock, which can significantly improve the temperature accuracy. A two-stage rectifier adopts a series of auxiliary floating rectifier to boost its gate voltage for higher power conversion efficiency. The sensor tag chip was fabricated in TSMC $0.18{\mu}m$ 1P6M CMOS process. The measurement results show that the proposed temperature sensor tag achieve a resolution of $0.15^{\circ}C$/LSB and a temperature error of $-0.6/0.7^{\circ}C$ within the range from $-30^{\circ}C$ to $70^{\circ}C$. The proposed sensor tag achieves maximum communication distance of 11.8 m.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.6
• /
• pp.2160-2179
• /
• 2015

In many Radio Frequency Identification (RFID) applications, the reader recognizes the tags within its scope repeatedly. For these applications, some algorithms such as the adaptive query splitting algorithm (AQS) and the novel semi-blocking AQS (SBA) were proposed. In these algorithms, a staying tag retransmits its ID to the reader to be identified, even though the ID of the tag is stored in the reader's memory. When the length of tag ID is long, the reader consumes a long time to identify the staying tags. To overcome this deficiency, we propose a slot allocated blocking anti-collision algorithm (SABA). In SABA, the reader assigns a unique slot to each tag in its range by using a slot allocation mechanism. Based on the allocated slot, each staying tag only replies a short data to the reader in the identification process. As a result, the amount of data transmitted by the staying tags is reduced greatly and the identification rate of the reader is improved effectively. The identification rate and the data amount transmitted by tags of SABA are analyzed theoretically and verified by various simulations. The simulation and analysis results show that the performance of SABA is superior to the existing algorithms significantly.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.1
• /
• pp.1-7
• /
• 2008

Today, Korean medical community faces rapid changes in medical environment due to opening of medical market, more emphasis on making profit and introduction of private medical insurance. Therefore, it is apparent that around, major university hospitals, efforts are being made to adapt to such changes by establishing mid to long range strategic plans. We want to keep pace with changing times and diverse demand of patients by introducing state of the art system, utilizing Ubiquitous technologies for improvements. In doing so, we want to distinguish our hospital services from others. However, Hospital Information System that integrates ubiquitous technologies are introduced in limited basis due to problems like standardization and limits on medical use etc. Particularly, problems like absence of tag design suitable for medical environment, compatibility and extension issue with RFID system need to be addressed on application of RFID technologies. In order to solve such problems, this paper implemented RFID tag system, RFID-SIP UA program, location tracking program. This paper provides a comprehensive basic review of RFID and SIP model suggests the evolution direction of further advanced RFID application service. The design of RFID-SIP application offers advance RFID system with drawback and reduction search time of medical object. so there is a improvement of hospital information system in ubiquitous environment.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.7 s.361
• /
• pp.9-15
• /
• 2007

In this paper, we present the design of Schottky diodes and voltage multiplier for UHF-band passive RFID applications. The Schottky diodes were fabricated using Titanium (Ti/Al/Ta/Al)-Silicon (n-type) junction in $0.35\;{\mu}m$ CMOS process. The Schottky diode having $4{\times}10{\times}10\;{\mu}m^{2}$ contact area showed a turn-on voltage of about 150 mV for the forward diode current of $20\;{\mu}A$. The breakdown voltage is about -9 V, which provides sufficient peak inverse voltage necessary for the voltage multiplier in the RFID tag chip. The effect of the size of Schottky diode on the turn-on voltage and the input impedance at 900 MHz was investigated using small-signal equivalent model. Also, the effect or qualify factor of the diode on the input voltage to the tag chip is examined, which indicates that high qualify factor Schottky diode is desirable to minimize loss. The fabricated voltage multiplier resulted in a output voltage of more than 1.3 V for the input RF signal of 200mV, which is suitable for long-range RFID applications.

• Proceedings of the IEEK Conference
• /
• 2005.11a
• /
• pp.1039-1042
• /
• 2005

Recently, a considerable number of studies have been made on the $RFID^{[1-6]}$ systems. RFID is a technique of identifying an object using radio frequency transmission. The technology can be used to identify, track, sort or detect a wide variety of objects. The RFID system is composed of two main elements: a reader and a tag. Tags can either be active (powered by battery) or passive (powered by the reader field). The passive tags communicate back to the reader with a technique called 'backscatter'. RFID technology can be applied to the supply chain, security, logistics industry and etc. Especially, UHF RFID is worth noticing because of its relatively long identification range and commercial UHF RFID systems are under development. In this paper, we designed and implemented a UHF RFID reader firmware for ISO/IEC 18000-6 Type B specification.

• Proceedings of the IEEK Conference
• /
• 2005.11a
• /
• pp.1049-1054
• /
• 2005

With the growth of RFID market in logistics industry, such as post office, airline, shipping etc., development of RFID readers and tags becomes crucial. Especially, $860{\sim}960MHz$ RFID is worth noticing because of its long identification range and low production cost. Therefore, performance tests and verification of reader and/or tag under development are very important. In this paper, a RFID emulator system is designed and implemented using a commercial CAD tool, a signal generator and a data acquisition device. With the RFID emulator system, many parameters such as spectrum masks, transmit power levels, data waveform and other RF characteristics can be analyzed. Furthermore it can be applied to the verification of real RFID Readers or Tags.