• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.3
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• pp.101-110
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• 2007

This study has designed a circular polarization antenna for UHF bandwidth RFID reader. As a result of performance test of the antenna designed it is found that return loss (S11) is about -45.529dB at 914MHz, which is relatively small, and antenna gain is about 6.09dBi. It has also been confirmed that $50{\Omega}$ impedance matching is about $50.48{$\Omega}$ and it can be applied to every RFID reader. Therefore, the antenna is designed to have higher gain of circular polarization by improving reception, which is one of the most important parameters of RFID reader and is expected to be extensively used to recognize multi-tag in the distance.

• Proceedings of the IEEK Conference
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• summer
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• pp.334-338
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• 2004

In this paper, we suggest a new antenna structure for RFID(Radio Frequency IDentification) reader. Conventional RFID reader uses a loop antenna. The central area of a loop antenna shows a low magnetic field strength especially for the case of a large loop antenna diameter. We propose a parallel-fed multiple loop antenna. Simulation results and measured results show that we can adjust field distribution with the number of turns and diameter of an inner loop antenna to obtain a longer reading distance. Simulation results for the specific case of a proposed antenna structure show that at the center point of a proposed parallel-fed multiple loop antenna, the typical card area averaged magnetic field strength is 2.53A/m, which is higher than the case of a conventional type single loop antenna of 0.44A/m and the case of a series-fed multiple loop antenna of 0.96A/m when we drive with same source signal. We realized the antenna for the case of 13.56MHz RFID reader and the performance of reading distance was much more improved than the case of a conventional antenna.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.1
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• pp.23-30
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• 2010

In this paper, a design for the 900MHz bandwidth RFID reader antenna with circular polarization is proposed and experimentally investigated. The 900MHz bandwidth RFID reader antenna is proposed as a simple radiator with loading capacitor to generate LHCP(Left Hand Circular Polarization). Also, the design and fabrication of antenna has the returnloss of -32.28dB at the center frequency of 1010MHz and Bandwidth of 12.5% at 905Hz~1030MHz. Proposed LHCP antenna of maximum gain is 6dBi and satisfy axial ratio based on 2. From the measured result, axial ratios based on 2 are observed at the operating frequencies. The proposed antenna is suitable for RFID applications in wireless communications.

• Journal of electromagnetic engineering and science
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• v.10 no.3
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• pp.79-85
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• 2010

In this paper, a directive antenna design with a combination of electric-magnetic radiators for an radio frequency identification(RFID) system is presented. To generate a directive antenna radiation pattern, a structure combining a dipole and loop antenna is presented. A reader antenna and tag antenna are proposed for the RFID system. For the reader antenna, the frequency bandwidth defined by $S_{11}$<-10 dB is approximately from 820~990 MHz. The forward and backward gain differences are 1.5~2 dBi. For the tag antenna, the frequency bandwidth is approximately from 860~920 MHz with a maximum gain of 3.58 dBi at 910 MHz. In both cases, directive radiation characteristics are observed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.648-650
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• 2015

In this research, we investigate an influence of a reader antenna location in Passive UHF RFID system based Object localization. When the localization system uses stationary RFID reader system, the performances of the system are significantly varied depending on the deployed antenna conditions due to its external environment such as reflection by the ground and obstacles. In this research we deeply study the RF conditions and differentiation with various antenna location. According to the empirical results, the localization system shows the best performance, where the reader antenna locates 1.5m from the target area of interest.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.151-154
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• 2007

This paper describes the project for constructing a traceability system for producing using RFID antenna in 900MHz frequency band and the consideration. In this project we reviewed analysis of properties classified by production process and RFID system through each frequency band, and designed a single unit RFID reader including antenna. The developed antenna is optimized to a field condition and this paper will show the test results. Also, we designed a single unit RFID reader by adding a reader to a designed antenna and explained the rule of tag memory allocation. Lastly, after running the system we could calculate visible and invisible effects of operation results and check up a wide possibility of application for RFID.

• Journal of the Korean Society for Railway
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• v.4 no.3
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• pp.102-109
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• 2001

In this paper, it has a proposal of the RFID reader antenna design that expand the dedicated short-range communication distance between a static object on the ground and a mobile object attached on the moving article. The static reader equipped with micro-processor makes it possible to have a serial communication with a main system, so that much data can be transfer to the main system. An antenna is adjusted in order to a communication, the scale is designed by results values of simulation using matlab. It is achieved to systematically manage logistics, person resource and security system by grasping the information and location of mobile object on the basis that this system receives the information between a static reader and a mobile object tag at 134.2kHz band on real time, also to make it possible the main system to process. Therefore, the reader antenna scale is controlled on the foundation of a magnetic field theory in order to expand a recognition distance of reader and tag, so that can be optimistically recognized with minimizing the direction influence of reader and tag.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1719-1724
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• 2013

In this paper, a size-reduction technique is presented for the RFID reader antenna working at two UHF bands. To tackle the problem of size increase in multi-band applications, two resonance paths are made to occur in one geometry with a single feed. While one resonance path is combined with the other, the entire geometry is determined to guarantee the resonance at the target frequencies through the dual-band input impedance matching. The antenna performance is predicted by the full-wave simulation, and the design method is verified by observing the good agreement between the simulated and measured results. At the two frequencies, the satisfactory return loss as well as the antenna efficiency and peak gain of the far-field pattern is obtained.

• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.40-50
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• 2009

Incorrect deployment of RFID readers occurs reader-to-reader interferences in many applications using RFID technologies. Reader-to-reader interference occurs when a reader transmits a signal that interferes with the operation of another reader, thus preventing the second reader from communicating with tags in its interrogation zone. Interference detected by one reader and caused by another reader is referred to as a reader collision. In RFID systems, the reader collision problem is considered to be the bottleneck for the system throughput and reading efficiency. In this paper, we propose a novel RFID reader anti-collision algorithm based on evolutionary algorithm(EA). First, we analyze characteristics of RFID antennas and build database. Also, we propose EA encoding algorithm, fitness algorithm and genetic operators to deploy antennas efficiently. To show superiority of our proposed algorithm, we simulated our proposed algorithm. In the result, our proposed algorithm obtains 95.45% coverage rate and 10.29% interference rate after about 100 generations.

• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.67-74
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• 2009

Incorrect deployment of RFID readers occurs reader-to-reader interferences in many applications using RFID technologies. Reader-to-reader interference occurs when a reader transmits a signal that interferes with the operation of another reader, thus preventing the second reader from communicating with tags in its interrogation zone. Interference detected by one reader and caused by another reader is referred to as a reader collision. In RFID systems, the reader collision problem is considered to be the bottleneck for the system throughput and reading efficiency. In this paper, we propose a novel RFID reader anti-collision algorithm based on evolutionary algorithm(EA). First, we analyze characteristics of RFID antennas and build database. Also, we propose EA encoding algorithm, fitness algorithm and genetic operators to deploy antennas efficiently. To show superiority of our proposed algorithm, we simulated our proposed algorithm. In the result, our proposed algorithm obtains 95.45% coverage rate and 10.29% interference rate after about 100 generations.