• Journal of electromagnetic engineering and science
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• v.18 no.1
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• pp.7-12
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• 2018

This article proposes an ultrahigh frequency band radio frequency identification (RFID) tag antenna for drug runout management that can be used in hospitals. The RFID tag antenna is designed to function as a sensor that alerts drug runout when a drug inside a drip chamber is completely consumed but does not work when a drug remains inside a drop chamber. A previously proposed 915 MHz dipole antenna, is too large to be attached to the drip chamber of a feeding bag. Moreover, the length of the dipole (L) should be increased for conjugate matching with an RFID chip. Therefore, the dipole antenna is downsized so that it can be attached to the drip chamber through a fine meander line structure coupling with a corrugate meander line. A transparent cover is added to enhance the grip force between the designed antenna and the drip chamber and to enable detachment. The dimensions of the completed antenna structure attachable to a drip chamber are 32.59 mm (height) and 13.5 mm (width). The gain reduction due to the decreased antenna length is enhanced. The fabricated antenna shows an average omni-directional read range of 10.65 m on a horizontal plane and has the function of sensing the presence of a drug.

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

• Journal of KIISE:Information Networking
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• v.34 no.5
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• pp.316-327
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• 2007

RFID (Radio Frequency Identification) is one of the most promising air interface technologies in the future for object identification using radio wave. If there are multiple tags within the range of the RFID tag reader, all tags send their tag identifications to the reader at the same time in response to the reader's query. This causes collisions on the reader and no tag is identified. A multi-tag identification problem is a core issue in the RFID. It can be solved by anti-collision algorithm such as slot based ALHOA algorithms and tree based algorithms. This paper, proposes a collision tree based anti-collision algorithm using collision tree in RFID system. It is a memory-less algorithm and is an efficient RFID anti-collision mechanism. The collision tree is a mechanism that can solve multi-tag identification problem. It is created in the process of querying and responding between the reader and tags. If the reader broadcasts K bits of prefix to multiple tags, all tags with the identifications matching the prefix transmit the reader the identifications consisted of k+1 bit to last. According to the simulation result, a proposed collision tree based anti-collision algorithm shows a better performance compared to tree working algorithm and query tree algorithm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.12
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• pp.1148-1157
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• 2013

In a passive UHF RFID system, the impedance matching between tag antenna and chip as well as the protocol parameter settings in a reader plays important role in determination of the maximum read-range. Almost no paper, however, has dealt with the above issues in relation with the maximum read range. In this paper, two known methods (of using the value from data sheets and proprietary RFID tester) and our proposing method in chip impedance evaluation are compared in terms of maximum read range. The read range of tags whose antenna impedance is conjugate matched with the chip impedance obtained from the proposed method is improved maximum 73 % more than that of tags from the other methods.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.10
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• pp.975-981
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• 2006

This paper shows a feasibility analysis results on RFID for car positioning system. Usually, a car navigation is mainly based on GPS combined with map-matching. However, in the case of poor visibility of satellites, GPS can not supply accurate position information continuously. In recent years, RFID has been considered to be one of key technologies in positioning and localization area. But its application and research results in the area of vehicular positioning are not popular. RFID system consists of tag, reader, antenna and software such as drivers and middleware. The main function of RFID system in a vehicular positioning is to retrieve ID recorded position information from tags which set on the center of road. We propose a positioning method for vehicles using RFID and we present some indoor and outdoor experiment results to show that the proposed method is available in vehicle operational environments.

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

• 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.

• Journal of Industrial Technology
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• v.28 no.A
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• pp.177-184
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• 2008

A low loss frequency doubler operated on low power for the RFID harmonic tags is presented. Using the excellent nonlinear characteristics of the Schottky barrier diode and proper matching networks between the diode and ports, the low conversion loss of the harmonic tag is accomplished. This doubler could be used to increase the detectable distance of the conventional RFID system adopted harmonic tags.