• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.12
• /
• pp.1228-1235
• /
• 2014

Input impedance of UHF RFID tag chip is needed to design a tag. In determining the chip impedance, direct measurement method is adopted commonly. In this paper, problems generated from fixtures that interface between tag chip and coaxial-oriented measurement instrument are investigated and the result of the problems is shown, when the direct measurement method is applied. As an alternative to the method, a modeling method is proposed and its validity and accuracy are shown.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.11 no.6
• /
• pp.581-590
• /
• 2016

This paper proposes an efficient collision avoidance algorithm that a group of RFID readers manage each of their affiliated active RFID tags in a space by establishing wireless network and avoids communication collision between RFID reader to reader and RFID tag to tag, and reader to tag. RF readers operate as wireless network nodes, create synchronous links each other, and can exchange messages. Active tags also are operated communicating each reader devices synchronously, and competing slot position between tags algorithm using unique tag identification number is implemented. Each reader node operates their own reader function different time slot network communication period to prevent collision between readers communication.

• The Journal of Engineering Research
• /
• v.7 no.1
• /
• pp.105-117
• /
• 2005

Because of the recent boost of the application services utilizing electronic tags, researches about the electronic tag management are widely being proceeded. In order to manage the object information collected from various electronic tags XML based data process, which is widely used on the web, is being demanded. Thus, in this paper, we are defining the re-usable object typer that is often used in this business area. Utilizing both the data type we defined and the Core Event Type defined from EPCIS Spec, we designed the scheme matching the object data model of merchant shipping field.

• Journal of Korea Society of Industrial Information Systems
• /
• v.15 no.3
• /
• pp.1-9
• /
• 2010

In recent year, the cores of ubiquitous environment are sensor networks and RFID systems. RFID system transmits the electronic information of the tag to the reader by using RF signal. Collision happens in RFID system when there are many matched tags, and it degrades the tag identification performance. Such a system needs algorithm which is able to arbitrate tag collision. This paper suggests a hybrid method which reduces collision between the tags, and can quickly identify the tag. The proposed method operates based on certainty, which takes an advantage of tree based algorithm, and to reduce collision it selects transmission time slot by using tag ID. The simulation results show the suggested method has higher performance in the number of queries and collision compared to other tree based and hybrid algorithms.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.18 no.4 s.119
• /
• pp.398-407
• /
• 2007

In this paper we proposed the tag antenna with a low performance distortion from an attached surface material using the asymmetric dual-arm dipole antenna(ADDA) structure. The tag is designed to exhibit low performance changes when the tag is attached on a target object(the medical litter receptacle, ${\varepsilon}_r=1.7,\;tan\;{\delta}=0.002$). Detail design parameters for the proposed antenna are optimized to maintain a good readable range in free-space as well as on a target object. The size of the optimized antenna is $100\;mm{\times}50\;mm$. The antenna shows the matching bandwidth($S_{11}$< -10 dB) of 3.7 % and the radiation efficiency of 80 % at the operating frequency. Finally we confirmed the readable range of the tag antenna by measurement and it shows about 5.3 m in free space and 5.5 m on the target object.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.16 no.2 s.93
• /
• pp.204-210
• /
• 2005

In this paper, we are proposed the antennas for RFID tag operated at UHF band which are inserted ground plane easy to mount the RFTD chips at the antenna surfaces. In order to implemented antenna for RFID tag which the size is same as conventional name card, the structure of the antenna is meander type, matching method for improvement characteristics of the antenna use T matching method, ground plane is inserted at the antenna substrate fer mounting RFID chips. The substrate size of implementation is $100\times60\;mm^2$ and the FR4 substrate is used. Results of the experiment, the center frequency of the implemented antenna is 427 MHz, -10 dB return loss bandwidth is 8 MHz, maximum return loss is 21 dB, the radiation pattern is omnidirectional. From these results, we are conformed application for UHF RFID tag antenna.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.04b
• /
• pp.55-56
• /
• 2009

Small RFID tag antenna were fabricated on Si substrate and their physical and electrical properties were evaluated. With decreasing the size of tag antenna on Si substrate, small SMD-type RFID tags could be fabricated, which is very useful for PCB tracking. Firstly, tag antenna pattern and the electromagnetic properties were simulated with HFSS. The frequency was 13.56MHz, the line-width and line-gap were modeled in the range of $50{\sim}200{\mu}m$. S parameters, SRF, and Q value were calculated from geometry. When the line-width and line-gap were 100um and the loop-turn was 10, the SRF was 80MHZ and the Q value was ca. 9. When the microstrip antenna pattern of aluminum was fabricated by using DC sputtering, Vpp of ca. 1.6V was obtained when the reader-tag distance was 40mm.

• Journal of the Institute of Convergence Signal Processing
• /
• v.19 no.3
• /
• pp.89-96
• /
• 2018

This study aims to develop a fully passive smart sensing tag utilizing RF (Radio Frequency) energy harvesting technology at UHF (Ultra High Frequency) band of 915MHz. To optimize the power collected under various radiated conditions, an efficient energy harvesting module exploiting a boost circuit with maximum power point tracking (MPPT) is employed. Specifically, the proposed tag features two orthogonal antennas to enhance its capability of both energy scavenging and data transmissions. The experimental result shows that the developed smart sensor tag can scavenge an RF input power of as low as 0.19mW at a distance of 4 meters for a 3.6Vdc output. Furthermore, the proposed smart sensor tag performs the feasibility of completely autonomous monitoring food freshness at 2 meters with a low-power sensor array.

• Journal of Internet Computing and Services
• /
• v.9 no.1
• /
• pp.43-54
• /
• 2008

In this paper, we implement an automatic entity information management system for smart refrigerator using RFID technology in which objects containing electronic tags are automatically identified using radio wave. Unlike current "smart" refrigerators, the system presented in this paper implements smart tag information acquisition mechanism and real-time information management system to provide various information on entities in refrigerators to local and remote users. As the first step, this paper analyzes the requirements for smart refrigerator system based on the RFID and suggests design considerations. Based on the analysis, we propose and implement an efficient tag location tracking method based on antenna transfer method and an intelligent tag information management system based on embedded database and web server. We also provide a wide range of experimental results on the number of tags identified at a time and the tag recognition ratio according to the RFID antenna transfer speed and the angle between tag reader and tags.

• Journal of Convergence Society for SMB
• /
• v.5 no.2
• /
• pp.21-26
• /
• 2015

Recently, NFC technology of short-range wireless communication using a smart phone to perform personal authentication with the electronic payment has been in the spotlight in various fields. However, the security associated with the personal information and the location information is vulnerable because it is easily fused with the existing mobile services and devices. In this paper, we propose a model for NFC payments help protect personal information and location information of NFC payment systems and services in various fields. Proposed model uses tag-based services in order to protect personal information and position information. The proposed model using the tag-based services is the place to check the various features available information in a simple Tag that can be easily accessed.