• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.5
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• pp.12-20
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• 2008

RFID(Radio frequency indentification) technology, that the reader detect the tag information attached on the objects without contact, is considered the kernel of realizing tile Ubiquitous Sensor Network. Particularly, because there are lots of tags(which the reader have to detect) in the UHF RFID system(that is applied at the Logistic & Distribution industry). In the UHF RFID system the negative effects, we called the tag-collision, may occur and we should solve these effects. So, in the EPCglobal Gen2 protocol they present the Slotted Random Anti-collision algorithm to prevent the tag-collision effect. In this paper, in order to minimize the tag-collision effect and bring on the system efficiency, we propose the Power Increasing Method that controls the transmission power of the reader depending on the environment and verily the improved performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1680-1685
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• 2011

This paper introduces UHF RFID tag antenna which can be inserted between the skin and muscle of animal. Animal Information Management System (AIMS) using the developed tag has been developed. Since the general and commercial tags are not working in the body of any animal, the new tag for flash body has been developed with the consideration of dielectric constant of the muscle and fat of animal. The tag shape is flat and sharp end to make it easy to insert the tag just under the skin. The performance of the installed tag under the skin and in the muscle has been verified. The AIMS can manage the animal, history of illness, information of owner and address. This program can be applied to the management of military and police dogs.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.152-160
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• 2008

In this paper, we analyze the performance of a direct-conversion UHF RFID reader with the range correlation effects of the phase noise. Since a UHF RFIB system uses the same oscillator to generate the transmitted carrier and the local oscillation, the periodic interference and phase noise reduction effects occur due to time delay between two signals. Through exact theory and simulation, we verify how to cancel the periodic interference phenomena using I/Q diversity combining technique. And, we analyze phase noise reduction effects due to range correlation as a function of the tag-reader distance and the offset frequency Using these results, we simulate the symbol-error-rate performance with respect to phase noise with and without range correation effects. We show that the phase noise of the local oscillator has little effect on the symbol-error-rate performance because of phase noise reduction by range correlation.

• Journal of Navigation and Port Research
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• v.32 no.5
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• pp.349-353
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• 2008

In this paper, the EM wave absorber was designed and fabricated for preventing Reader Interference of RFID communication system in UHF band We fabricated several samples in different composition ratios of Amorphous and CPE(Chlorinated Polyethylene). Absorption abilities were simulated in accordance with different thicknesses of the prepared absorbers and changed complex relative permittivity and permeability due to composition ratio. The mixing ratio of Amorphous and CPE was searched as 80 : 20 wt.% by experiments and simulation. Then the EM wave absorber was fabricated and tested using the simulated data. As a result, the developed EM wave absorber has a thickness of 4 mm and absorption ability was over 20 dB in frequency range of $860\;MHz{\sim}960\;MHz$. Therefore, it was confirmed that the developed absorber can be used for suppressing RFID reader interference in UHF band.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.9
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• pp.41-49
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• 2008

This paper presents a design of the control block of a passive UHF RFID tag IC according to EPCglobal Class-1 Generation-2 UHF RFID 1.1.0 Protocol. The control block includes a PIE block, CRC5/CRC16, a Slot Counter, a Random Number Generator, a Main Control Block, a Encoder and a Memory Interface. The control block has been designed using the Verilog HDL and has been simulated. Functional simulation results for the overall control block operation show that 11 instructions with 7 states are operated correctly. Also, the control block has been implemented with 36,230 gates by Synopsys Design Compiler and Apollo using Magnachip 0.25$\mu$m technology.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.9
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• pp.67-74
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• 2016

This paper presents a novel multiple orthogonal subcarrier modulation based UHF band RFID communication system. In tag-to-reader communication, the demonstration system can deliver 1.6 Mbps through four subcarriers. To improve data rate while suppressing increase in circuit complexity, tag employs square-waves as the subcarriers and uses individual load modulators for each subcarrier. By using multiple orthogonal subcarrier based modulation, proposed communication system can be operated under existing UHF band RFID regulation. In reader, an OFDM demodulator is used. Since the tag backscatters the reader's CW carrier, carrier frequency offset compensation is not necessary in reader demodulator. Experimental results show that the demonstration system achieves a bit error rate of 10-5 at an Eb/N0 of 10.8 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.9
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• pp.679-684
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• 2017

This paper presents an UHF(Ultra High Frequency) band small cavity structured RFID(Radio Frequency Identification) tag antenna with a long reading range, designed to apply on metal cart or pallet for auto-parts logistics. The size of tag antennas is $140{\times}60{\times}10mm^3$, attached on a exporting metal cart, and it can give the information of inventory and logistics of carts. By collecting the exported carts and increasing the recovery rate of missing carts or pallets, the paid import tax can be refunded when the carts are returned back to the manufacture. The tag antenna was equipped with a cover to prevent damage, and the dielectric constant of the cover is considered for the simulation. The reading range of the tag antenna is 12 m using LP(Linear Polarization), 10 m with CP(Circular Polarization) reader antennas. This 920 MHz UHF RFID cavity tag ensures the long reading distance of the antenna regardless of the material of the object where it is attached.

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

• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.99-112
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• 2008

In the passive UHF (860-960MHz) RFID communications, which consists of a set of readers and tags, the readers normally interrogate the tag by using the backscatter mechanism. (i.e., tag response). In practical RFID environment, where multiple readers or tags exist; the interference causes collisions. This paper proposes a centralized arbitration scheme for avoiding the collision problems among multiple readers. The proposed centralized arbitration scheme is modeled in software environments, and is verified with simulation results. Simulated performance is focused on completion time, utilization and response time, and the simulation results show that our proposed scheme provides satisfactory performance grade.

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