• ETRI Journal
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• v.28 no.3
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• pp.383-385
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• 2006

A new meander-line antenna consisting of two open-ended strips is proposed for a compact and broadband UHF radio frequency identification tag. An equivalent circuit model for the proposed antenna is derived and used to perform a simple and wideband impedance match to an arbitrary complex impedance of a tag chip without any additional matching network. The performance of the proposed antenna is validated by comparing calculated and measured results, which show good agreement.

• Journal of Korea Multimedia Society
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• v.14 no.2
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• pp.194-200
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• 2011

Recently, RFID(Radio Frequency IDentification) market spread in industry region is entering a phase of stagnation due to cost issue. RFID tag inlay cost has become relatively more expensive due to the recent decrease in chip price. Therefore, a simple and rapid design technique for RFID tag has yet to be implemented to achieve low cost. This paper presents a design technique considering chip impedance for antenna design for improved accuracy and computation time. As a result, it is confirmed that analysis error for resonance ranges within 20MHz and readable range error falls within 1.5m.

• Journal of Korea Multimedia Society
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• v.15 no.11
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• pp.1358-1368
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• 2012

A tag sequence estimation scheme is to estimate the physical sequence of passive RFID tags that are linearly spread using the movement of a RFID reader. Since RFID readers communicate with the passive tags by very weak radio waves, scanning passive tags are unstable. In this paper, we applied round-trip scanning of a reader to enhance the tag sequence estimation. Proposed scheme first determines the turning point of the reader movement, and then estimates the sequence of the tags using the tag sets scanned in each read cycles. Test experiments show that the proposed scheme can improve the estimation accuracy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.636-637
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• 2018

The electronic shelf label(ESL) system based on wireless communication can reduce waste of disposable paper, reduce labor force and update real time information. However, the environment in which a large number of ESL modules are installed is exposed to interference from radio frequency(RF) communications in the Industry-Science-Medical(ISM) band. In this paper, we propose an ESL system based on visible light communication to avoid congestion of ESL system using ISM band. In the proposed system, the goods information and ID transmitted from the administrator server are transmitted in the ESL Tag, and the ESL Tag identifies the ID and displays the product information. Experiments show that ESL system using visible light communication is possible.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.66.1-66.1
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• 2012

Although all printed cost-less radio frequency identification (RFID) tags have been considered as a core tool for bringing up a ubiquitous society, the difficulties in integrating thin film transistors (TFTs), diodes and capacitors on plastic foils using a single in-line printing method nullify their roles for the realization of the ubiquitous society1,2. To prove the concept of all printed cost-less RFID tag, the practical degree of the integration of those devices on the plastic foils should be successfully printed to demonstrate multi bit RFID tag. The tag contains key device units such as 13.56 MHz modulating TFT, digital logic gates and 13.56 MHz rectifier to generate and transfer multi bit digital codes via a wireless communication (13.56 MHz). However, those key devices have never been integrated on the plastic foils using printing method yet because the electrical fluctuation of fully printed TFTs and diodes on plastic foils could not be controlled to show the function of desired devices. In this work, fully gravure printing process in printing 13.56 MHz operated 32 bit RFID tags on plastic foils has been demonstrated for the first time to prove all printed RFID tags on plastic foils can wirelessly generate and transfer 32 bit digital codes using the radio frequency of 13.56 MHz. This result proved that the electrical fluctuations of printed TFTs and diodes on plastic foils should be controlled in the range of maximum 20% to properly operate 32 bit RFID tags.

• Journal of Communications and Networks
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• v.14 no.1
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• pp.34-39
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• 2012

Collisions between tags greatly reduce the identification speed in radio frequency identification (RFID) systems and increase communication overhead. In particular for an active RFID system, tags are powered by small batteries, and a large number of re-transmissions caused by collisions can deteriorate and exhaust the tag energy which may result in missing tags. An efficient collision-free arbitration protocol for active RFID systems is proposed in this paper. In this protocol, a new mechanism involving collision detection, collision avoidance, and fast tag access is introduced. Specifically, the pulse burst duration and busy-tone-detection delay are introduced between the preamble and data portion of a tag-to-reader (T-R) frame. The reader identifies tag collision by detecting pulses and transmits a busy tone to avoid unnecessary transmission when collision occurs. A polling process is then designed to quickly access the collided tags. It is shown that the use of the proposed protocol results in a system throughput of 0.612, which is an obvious improvement when compared to the framed-slotted ALOHA (FSA) arbitration protocol for ISO/IEC 18000-7 standard. Furthermore, the proposed protocol greatly reduces communication overhead, which leads to energy conservation.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.2
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• pp.158-163
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• 2010

In this paper, we propose the location measurement algorithm of unknown tag based on RFID (Radio-Frequency IDentification) by using RSSI (Received Signal Strength Indication) and TDOA (Time Difference of Arrival) and extended Kalman filter in smart space. To do this, first, we recognize the location of unknown tag by using the RSSI and TDOA recognition methods. Second, we set the coordinate of the tag location measured by using trilateration and SX algorithm. But the tag location data measured by this method are included complex environmental error. So, we use the extended Kalman filter in order to revise error data of the tag location. Finally, we validate the applicability of the proposed method though the simulation in a complex environment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.6
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• pp.535-543
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• 2009

This paper describes a design for RFID(Radio Frequency Identification) tag antenna using license plate attached the vehicle bumper in 900 MHz band. The proposed tag antenna size which is located on upper center position of a vehicle license plate is 162.5${\times}$40${\times}$1 mm$^3$. A resonant frequency of design antenna and the bandwidth which has return loss of -10 dB below are 900 MHz and about 720 MHz(640${\sim}$1,360 MHz), respectively. The commercial chip impedance considered on design was 16- j131 ${\Omega}$ and the complex conjugate impedance of chip was used as input impedance of tag antenna. The measured return loss and radiation pattern were agreed well with the calculated results. The measured readable range of the proposed tag antenna designed on only the vehicle license plate was 11.5 m. Moreover, its range of the fabricated tag antenna that the license plate and the vehicle bumper were fixed by volt and nut was observed 10.4 m. These measured readable range showed about 5 m above far distance more than the average readable range of commercial tag antenna.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.12
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• pp.983-990
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• 2013

In this paper, we proposed a Hangul type chipless RFID tag, which has better legibility than the conventional chipless RFID tag not only to a computer but also to a human. We made consonant model, vowel model and whole character model by WIPL tool and checked the applicability of Hangul type chipless RFID tag. We obtain the RCS pattern of each character by simulation. Finally, We classify the character from input data in noisy environment using a variance of the data.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.259-259
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• 2006