• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.10
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• pp.45-52
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• 2008

We investigated the design of an RF-powered, wireless temperature sensor tag chip using $0.18-{\mu}m$ CMOS technology. The transponder generates its own power supply from small incident RF signal using Schottky diodes in voltage multiplier. Ambient temperature is measured using a new low-power temperature-to-voltage converter, and an 8-bit single-slope ADC converts the measured voltage to digital data. ASK demodulator and digital control are combined to identify unique transponder (ID) sent by base station for multi-transponder applications. The measurement of the temperature sensor tag chip showed a resolution of $0.64^{\circ}C/LSB$ in the range from $20^{\circ}C$ to $100^{\circ}C$, which is suitable for environmental temperature monitoring. The chip size is $1.1{\times}0.34mm^2$, and operates at clock frequency of 100 kHz while consuming $64{\mu}W$ power. The temperature sensor required a -11 dBm RF input power, supported a conversion rate of 12.5 k-samples/sec, and a maximum error of $0.5^{\circ}C$.

• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.47-53
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• 2011

The detection process of defective tags in most of Korean domestic RFID manufacturing companies is treated by on-hand processing after the job of chip bonding, so it has been requested to reduce the time and cost for manufacturing of RFID tags. Therefore, in this paper, we implement the system to perform the detection of defective tags after the process of chip bonding, and so provide the basis of software to establish the foundation of automation system for the detection of defected RFID tags which is requested in the related Korean domestic industrial field. We have developed the system by using UML in modeling phase and JAVA in implementation phase to reduce the cost of development of program and make it easy to maintain. The developed system in this paper shows the very enhanced performance in processing speed and perfect detection rate of defective tags, comparing to the method of on-hand processing.

• Journal of the Korea Society of Computer and Information
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• v.18 no.9
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• pp.11-19
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• 2013

Most modern computer systems employ cache systems in order to alleviate the access time gap between processor and memory system. The power dissipated by the cache systems becomes a significant part of the total power dissipated by whole microprocessor chip. Therefore, power reduction in the cache system becomes one of the important issues. Partial tag cache is the system for the least power consumption. The main power reduction for this method is due to the use of small partial tag matching, not full tag matching. In this paper, we first analyze the previous regular partial tag cache systems and propose a new address matching mechanism by using locality buffer and address compression. In simulation results, the proposed model shows 18% power reduction in average, still providing same performance level, compared to regular cache.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.9
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• pp.978-984
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• 2008

In this paper, we propose a RFID metal tag antenna with a minimum by size of a metal surface to attach. This proposed tag antenna is a patch antenna which is able to stick on metal surface and designed for very slim structure ($119{\times}30{\times}1.6$ mm) antenna that is matched to a chip impedance. This has a loop coupling feeding and consists of a inner radiator and a outer radiator. The outer radiator activates the current to concentrate on the inner radiator regardless of metal size to attach. Also the tag antenna is designed by CST microwave tool and the performance is measured in the anechoic chamber. The optimum antenna has 3.77 % of the matching bandwidth($S_{11}<-10$ dB). The readable range of the tag antenna is about 2.9 m on metal(max. size $700{\times}700$ mm) and 5.5 m in free space according to the measurement results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1452-1458
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• 2009

In this paper, Our proposed Multipurpose Complex Card UHF band RFID small-size Tag antenna. Multi purpose Complex Card UHF band RFID small-size Tag antenna that is to minimize the low efficiency of RFID Tag Read Range that generates space limitation and a conductor surrounded by inducing fingerpring system with dual(HF, UHF) Card is presented. Our proposed UHF band RFID small-size Tag antenna is for the Multipurpose Complex Card that is mounted on the fingerpring system as well as the HF Tag. It also enables to minimize and facilitates Tag chip matching by adjusting Tapered, Meander line and Loop structure. Given the card substance properties and periphery circuit, the proposed small-size Tag antenna, in this report, is designed with PET film with size of $50{\times}15mm^2$. The RFID small-size Tag method for measurements is used by EPCglobal Static Test instrument in Anechoic Chamber, which is tested with dual Card, within the car and in wallet. It is found that Read Range is 3.8m from the EPCglobal Static Test, Maximum Read Range within the car from the field test results in 7.6m. Proposed Tag antenna is will be used in the parking control security system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.280-284
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• 2005

In ubiquitous computing environment, An RFID system will be the important way that recognizing an object instead of Bar-code system. But a privacy infringement problem is predicted between a tag and leader to be serious. There is many difficulty that just uses an existing research method because it has an Hardware restriction. Therefore we will suggest that A RFID Privacy Protect system using Hareware friendly security algorithm. we will use RC5 and CBC_MAC because the tag has hardware restriction .To implement, We will simulate and test on One chip microprcessor environment. In the result of the experiment, We will know that a suggested system solves privacy problem on RFID system that it was using CBC-MAC and RC5 security algorithm.

• Journal of the military operations research society of Korea
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• v.31 no.1
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• pp.58-72
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• 2005

RFID(Radio Frequency Identification) is one of key technologies in ubiquitous computing. RFID system comprises tag, reader, and computer application. The tag is a small electronic chip, which is attached to a thing such as item, pallet, container. The reader has an tiny antenna obtaining the identification information of the things by radio frequency, and provides the information to the computer application for a business. In this paper we have proposed the military application of RFID and its implementation policy for the Korean armed forces. We believe that The principle application area would be logistics TAV(total asset visibility) and resource management, and the implementation should be achieved step by step considering the advancement of RFID technology and government policy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.47-49
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• 2011

21세기 새로운 IT 혁명인 유비쿼터스 환경을 목표로 여러 IT 분야들은 모든 사물의 지능화를 위해 여러 기술들을 탐구하고 있다. 그 중의 하나인 RFID 시스템은 비접촉 대상물 인식을 수행하는 무선 통신 기술이다. Tag와 Reader간의 비접촉인식을 이루는 RFID 시스템은 Reader IC인 U2270B 칩이 핵심이다. 효율적으로 U2270B의 사용을 위해서는 RFID reader의 안테나 설계, 안정화된 전력공급, 그리고 작동모드 제어 등의 전반적인 기술적 이해가 필요하다. U2270B의 동작을 위한 구성은 안테나를 통한 전자장 형성과 전자유도 결합으로 동작하는 Tag와의 통신이다. 본 연구에서는 저주파수 대역 RFID Reader에 사용되는 U2270B의 구성에 대한 기본 개념과 H/W 구현에 대하여 설명하고, 실제 구현된 시스템과 각 부분의 실측 파형을 제시함으로써 환자 인증용 RFID 시스템 적용방안을 제시하고자 한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.5
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• pp.480-492
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• 2009

In this paper, we proposed a broadband U-shaped RFID tag antenna with near-isotropic characteristic at UHF band. The proposed tag antenna is composed of the U-shaped half wavelength dipole and a rectangular shaped feed. The rectangular shaped feed that is located inside U-shaped dipole is connected for conjugate impedance matching with the commercial tag chip. A better constant gain deviation characteristic in the operating frequency band is achieved by inserting a rectangular slit in the lower center of the U-shaped antenna body. On the condition of VSWR<2, the tag antenna had the measured bandwidth of 10.36%, from 860.5 to 954.5 MHz, and 9.84%, from 864.5 to 954 MHz, for antenna without slit and with slit, respectively. On the condition of VSWR<5.8, the tag antennas had the measured bandwidth of 15.78%, from 835.5 to 979.5 MHz, and 15.89%, from 837 to 981.5 MHz, for antenna without slit and with slit, respectively. The difference between the maximum and minimum gain deviations of tag antenna without slit in the operating frequency band is 0.53 dB since the maximum and minimum gain deviations are 3.86 dB and 3.33 dB, respectively. Whereas the difference between the maximum and minimum gain deviations of tag antenna with slit in the operating frequency is 0.06 dB since the maximum and minimum gain deviations are 3.60 dB and 3.54 dB, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.9
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• pp.598-605
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• 2014

In this paper, we suggest a modified slotted ALOHA algorithm for fast tag collection in active RFID system and implement the reader and tag operation using CC2530 chip of Texas Instruments Co. to prove the performance of the proposed algorithm. In the present international standard related with active RFID including ISO/IEC 18000-7 the reader sends sleep command to each tag after successful obtaining tag's information. Meanwhile, in this paper, the tags decide to sleep after checking the second command from the reader resulting in enormously decreased tag collection time. We tested the proposed algorithm with 30 tags over the range of 0-3m and the results showed that the tag collection process was completed in 400msec at average. And 30 tags are collected in one second with 99.7% and the collection rate is 100% in 2m distance between reader and tag. The collection rates are 99.94% and 99.7% for distance 2.5m and 3m, respectively. The average collection rate is 99.91% over all range and it is concluded that the proposed algorithm is enough to apply to real fields.