• Journal of Korea Society of Industrial Information Systems
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• v.16 no.4
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• pp.1-7
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• 2011

In this paper, we design rectifing circuits at 910MHz, which is used for passive RFID system, for wireless power transmission system by using two types of schottkey diodes HSMS_2822 and HSMS 2852, and the RF-DC conversion efficiencies for the curcuits are compared and analyzed in terms of input power and load resistance. When the input power is -20 to 17dBm, the conversion efficiency for HSMS_2852 is larger than in case of HSMS_2822. The output voltage and current at the load of the fabricated rectifying circuit are measured through a dipole antenna when input power is transmitted by a RFID reader and the diatance varies. The measured ouput volatge and current for the distance of 50cm are 2.5V and 5.75mA.

• Journal of Sensor Science and Technology
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• v.21 no.2
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• pp.103-108
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• 2012

Radiofrequency(RF) signal is a key medium to the most of the present wireless communication devices including RF identification devices(RFID) and smart sensors. However, the most critical barrier to overcome in RFID application is in the failure rate in detection. The most notable improvement in the detection was from the introduction of EPC Class1 Gen2 protocol, but the fundamental problems in the physical properties of the RF signal drew less attention. In this work, we focused on the physical properties of the RF signal in order to understand the failure rate by noting the existence of the ground planes and noise sources in the real environment. By using the mathematical computation software, Maple, we simulated the distribution of the electromagnetic field from a dipole antenna when ground planes exist. Calculations showed that the dark area can be formed by interference. We also constructed a test system to measure the failure rate in the detection of a RFID transponder. The test system was composed of a fixed RFID reader and an EPC Class1 Gen2 transponder which was attached to a scanner to sweep in the x-y plane. Labview software was used to control the x-y scanner and to acquire data. Tests in the laboratory environment showed that the dark area can be as much as 43 %. One who wants to use RFID and smart sensors should carefully consider the extent of the dark area.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.4
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• pp.537-542
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• 2014

Track circuit is a simple electrical device which lies in the connection of the two rails by the wheels and axle of locomotives and rolling stock to short out an electrical circuit, used to detect the absence of a train on rail tracks. In railway signaling system, there are similar systems such as RFID and wheel sensor, GPS etc, are research and developing. Hybrid track circuit is using RFID antenna and reader on the cab and RFID tag on the sleeper. because of the safety in railway operation, tag detection of train position detection function in the hybrid track circuit needs high reliability. This paper studied tag recognition enhancement used tag angles.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.4
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• pp.833-838
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• 2011

RFID system in manufacturing industry is used to collect, categorize, and process the data of products. To install RFID system for a large factory, a large amount of wired data communication network is necessary for RS232 communication. If the installed location of RFID system in the factory is changed or extended, a reinstallment is required for the already installed wired data network. A large amount of time/financial reinvestment is necessary for such reinstallation. By using wireless data communication network, however, the initial installation and reinstallation are very simple. In this paper, we implemented a wireless communication system and RFID system. We used the CC1020 chip for wireless communication system and EM4095 chip for RFID system. CC1020 chip enables highly-reliable data communication, and by setting a simple status register, it can switch between transmitting/receiving status and it can choose the desired frequency of either 400 MHz or 900 MHz. Also, Communication range is 50 m, if external antenna is used. EM4095 is a chip for RFID reader system with the carrier frequency of 125 KHz. This chip can implement the reader system by connecting a small number of components. And EM4100 was used for RFID system. EM4100 is read-only type. Atmega128 is used to control a wireless communication system and RFID system. We confirm that the system can communicate without error up to 50 m from sender. In the paper, the circuit diagram and operation program for CC1020 and RFID system are presented. The system used in the experiment is shown in pictures, and the data movement pattern of CC1020 is shown in the diagram, and the performance of each transmission method is presented.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.55-57
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• 2022

In this study, a customized semi-passive RFID receiver module was implemented for in-VIVO deep tissue photo-therapy. A novel wireless technique is required due to a limitation of RF communication in body environment, as internal body has a complex structure such as, skin, fat, skeleton, water, and so on. Recently, coherently incoherent beamforming (CIB) based on RFID was introduced and it is able to transmit wireless signal with high reliability under the incoherent condition such as in-VIVO deep tissue. The proposed miniature photo capsule based on RFID consists of miniature controller, ultra small LED array and wireless RFID chip. RF Reader can access with standard RFID protocol (ISO 18000-6c) using UHF RFID antenna, a control command is wirelessly writtern on USER Bank memory. With received control command, therapy LED array dims with mulilevel under timer control. The signal process of designed RFID photo therapy capsule is analyzed and evaluated under the various environments in detailed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.1
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• pp.99-107
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• 2008

Recently route guiding system using GPS is spread widely. In the parking management system of complex mall, RFID is mainly used to control status of parking lots. However, in a case that a vehicle only with RFID tag enters into small market-populated district with service of parking lots, there is no parking route guiding system optimized with information of real tine status of parking lots and the system only with GPS can't provide a function of using real time status of parking lots. This paper proposes a location recognizing method of RFID tag object for parking control system to integrated several parking lots in the business district and database-linked route guiding system optimized for parking. The proposed location recognizing method makes the search of optimized parking route possible by abstracting decoding order of tag and antenna number and recognizing direction of tag linked with database. Ihe implemented system that is composed of RFID tag, reader, middleware, server, parking lot clients and mobile clients shows that the proposed method works well and it will be useful for integrated parking control system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5C
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• pp.429-436
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• 2012

In this paper, an RFID system for the automatic preparation system of positron emission tomography (PET) radiopharmaceuticals is developed. Since the preparation system uses radioactive isotope, the preparation system is generally placed in lead-shielded hot-cell. Disposable cassettes including tubes and valves are used in the preparation system, since they are easily contaminated by radioactivity during preparation of radiopharmaceuticals. Currently, a system for preventing re-use of the cassette and managing the information about the preparation precess and result independently from the PC which control the preparation system is highly required for preventing danger from the radiation accident. Since RFID can store and re-write relatively large amount of information, it is suitable for the purpose. However, it is hard to read multiple cassettes' information using antennas installed on the metallic surfaces with current RFID systems. For the problem, we improve RFID system in two directions. First, the interface of the RFID reader is changed then it is possible that multiple readers can be daisy-chained. Also, antenna is tuned while inserting in a metallic coated antenna case, then the effect from the metallic surface of the preparation system is minimized. The test result using the developed system shows that the developed RFID system can read multiple tags using the antennas which are attached on the metallic surface.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.119-123
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• 2006

Finding out the exact location of survivors in short period of time is critical to conduct rescue activity successfully in oceans. Current technology with natural circumstances limits the activity that our efforts come along. R&D Center housed at Korea Coast Guard (KCG) has developed the system named "RFID for Life jacket" which enables us to access the location of persons under distressed situation. The RFID has been widely known as state-of-art technology to monitor the location even in inland or in ocean. Composed of tag, antenna. reader and middleware, RFID is attached to attached to a life jacket that people usually wears in recreational activity. By conducting experiments in pilot-scale several times, successful results showing 96.7% of transmission within 3.5km in diameter were produced. This study explains the routes of experiments to reach the goal and expected results coming from this accomplishments.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1585_1586
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• 2009

본 논문에서는 다구찌 기법을 사용하여 최적설계 한 중심 주파수가 920MHz인 휴대용 RFID 리더안테나를 제안한다. 제안한 안테나는 모서리가 절단되고 정사각형 마이크로스트립 패치에 네 변으로부터 슬롯을 갖는 구조이다. 이러한 슬롯구조는 마이크로스트립 패치안테나를 소형화 시킬 수 있으며, 슬롯이 없는 구조에 비해서 약 18%의 안테나 크기 감소가 가능함을 실험을 통해 확인 하였다. 슬롯의 구조를 갖게 되는 소형의 안테나는 복잡한 설계변수에 따라 변화하므로 최적의 안테나 설계를 위해서는 해석 및 시험단계에 수많은 반복이 요구된다. 본 연구에서는 해석 및 실험 횟수를 최소화할 수 있는 실험계획법인 다구찌법의 직교배열 표를 도입하여 설계할 때의 주요 요소들의 민감도 해석을 수행하고 그 영향성을 분석하여 해석결과를 바탕으로 설계반복을 최소화 하면서 최적의 구조를 갖는 안테나를 설계 하였으며 유전율이 4.4이고, 두께가 3.2mm 인 Epoxy 1.6T의 기판상에 제작한 안테나 특성에 대한 실험 결과를 제시하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8760-8766
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• 2015

In this paper a technology which gives directions to people and also localization of the robotic vacuum cleaners inside some spacious buildings is developed. For this purpose, it is confirmed that which pattern has a small error in dealing with the indoor localization with various RFID tag arrangements attached on the ground. This experiment was conducted by using MT92(900MHz range Antenna) and ALR 9900+(Reader). As a result, the square arrangement has the least error, 21.19cm, among other patterns which are diamond, rectangle and regular hexagon. However, it is necessary to consider the number of tags in the unit area, from this point of view the regular hexagon arrangement is the most efficient arrangement among other patterns because it needs only 6 tags in the unit area.