• Journal of IKEEE
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• v.24 no.1
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• pp.368-371
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• 2020

In this paper, we propose a linear tapered slot rectifying antenna for a portable UHF-band RFID system. Since the proposed rectifying antenna does not use a dielectric substrate, the planar antenna is implemented with a thin metal thickness. The rectifier circuit converts input RF power into output DC voltage using a voltage doubler circuit based on two anti-parallel schottky diodes. The rectifying antenna is integrated by the voltage doubler circuit into a linear tapered slot antenna. For conjugate impedance matching of the rectifying circuit and the linear tapered slot antenna, the source-pull method was utilized by adjusting the angle of the tapered slot and the length of the antenna feed line. The proposed antenna prototype has been verified with the electrical and radiation characteristics through RF-DC conversion and far-field radiation test in open space measurement environment. Finally, the proposed antenna is realized to 0.23-wavelength (75 mm) and 0.18-wavelength (60 mm) at 915 MHz center frequency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.1C
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• pp.34-37
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• 2012

The paper introduces the an necklace type UHF RFID tag for a live tree having high dielectric constant. When a general UHF RFID tag is used for the metal and the material with high dielectric constant, the electrical characteristics and impedance of antenna have been changed, and the tag is not recognized by an UHF RFID reader. The necklace type UHF RFID tag has been designed with consideration of the high dielectric constant of the tree material. The name tag for a live tree has been designed with the developed tag antenna. The performance of tag has been measured and the reading range is about 4~5m. The developed UHF RFID tag antenna can be applied to any high dielectric material for various industrial applications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.2
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• pp.93-98
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• 2018

This paper introduces the development of HF(NFC) and UHF band(13.56 MHz, 920 MHz) tag antennas, imbedded in a box. In dual band antennas, the HF band tag can be used to inspect the box using NFC, and the UHF band tag can be used for logistics. The dielectric constant of the box material is measured and used for simulation. The Ntag213 chip manufactured by NXP is used in HF loop antennas, since NFC is possible with Ntag213. For the UHF band, the Higgs-3 chip manufactured by Alien is used. The HF tag antenna is located at the center of the UHF tag antenna, and the location of the HF tag antenna is calculated while considering coupling effects. The designed tag can be used by both the bands for the purposes of logistics and authentication.

• 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 Institute of Information and Communication Engineering
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• v.19 no.8
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• pp.1759-1764
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• 2015

In this paper, we considered a design method of a circular polarization (CP) antenna for UHF (ultra high frequency) RFID (Radio Frequency IDentification) readers. The antenna is a dual-fed circular microstrip patch which produces right-handed CP. Quadrature hybrid coupler is used for dual feeding. The outputs of the coupler and circular patch are connected through copper wires, and the inductive reactance produced by the connecting wires is compensated by a ring-shaped slot inserted inside the circular patch. The effects of the geometrical parameters of the proposed antenna on the antenna performance are examined, and the parameters are adjusted to be suitable for the operation in North American UHF RFID band (902-928 MHz), which includes domestic UHF RFID band. The antenna is fabricated, and the experiment results reveal a frequency band of 854-993 MHz for a voltage standing wave ratio < 2. The fabricated antenna is connected to a commercial RFID reader, and it showed a good performance of tag identification.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.5
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• pp.47-52
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• 2008

In this paper partial discharge were simulated by conducted particle, a fine protrusion, surface discharge, which could be easy accumulated charge and concentrated electric field in the model GIS. In this times this paper measured and analyzed the radiated electromagnetic waves by using spectrum analyzer and antenna ($30{\sim}2,000[MHz]$ for measurement of EMI EMC in accordance with occurrence and propagation of partial discharge. In the basis of this results, a novel UHF(Ultra High Frequency) spherical sensor is presented. The measured impedance bandwidth of the proposed antenna is from 0.3[GHz] to 1.7[GHz]. Form results of this study, this antenna will be playing an important role for the sensor for insulation diagnosis system by UHF method of real site GIS and power equipment using $SF_6$ gas.

• Journal of the Korea Convergence Society
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• v.6 no.1
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• pp.109-114
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• 2015

A circularly polarized small UHF RFID reader antenna is presented. The antenna is composed of four elements and printed on the plastic substrate(${\varepsilon}_r=2.2$, t=5mm). Each element is fed by a probe which is sequentially connected to the feed line. The feed line is manufactured on the FR-4 substrate(t=1.0mm, ${\varepsilon}_r=4.7$). The simulation results shows that the antenna can be achieved a return loss of 12dB, gain of 3.46dBic over the UHF band of 902-928MHz. According to our simulation results, two prototype antennas are manufactured and measured. The obtained antennas operate in UHF RFID bands and can be adapted for various portable applications. In addition, a parametric study is conducted to facilitate the design and optimization processes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.11
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• pp.982-989
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• 2013

Omni-directional antennas of UHF-Band are located on the top and bottom side of the Smart UAV in order to connect a link always. Therefore one of each antennas should be connected to a ground antenna. Because the communication link of the omni-directional antennas is influenced by the objectives around aircraft, the clearance of LOS(Line of Sight) should be achieved in order to avoid a loss of link. In this paper, the analysis results on the influence of the complex objectives placed around the antenna on the communication link are presented according to the change of attitude angles. The best positions of antennas are selected based on the electromagnetic analysis using XGTD tool which supports the modeling of antenna pattern. The flight tests of the Smart UAV were successfully performed with the selected antenna position.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.270-273
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• 2012

A plastic bolt shape UHF RFID tag has been developed for a live tree. The UHF tag is designed and installed into the head part of the bolt, inserted into a tree for management of tree. If the tag antenna is installed near the high dielectric constant material, the impedance of the tag antenna will be changed, and the tag does not work. Therefore, the dielectric constants of wood and plastic bolt are considered for tag antenna design. The input reflection coefficient characteristics and the reading range patterns are measured and compared. This UHF RFID tag can be applied into a live tree, and the status and location of tree can be controlled with the RFID tag. This developed UHF tag can be applied to any applications and objects using a bolt.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1897-1899
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• 2003

본 논문에서는 Barrier coupler type UHF 센서의 현장적용 및 감도개선을 위해 외부잡음의 차폐방법과 광대역 안테나를 Barrier coupler type UHF센서에 적용시켜 센서의 성능을 개선시켰다. GIS 내부에서 발생하는 부분방전 신호를 검출하기 위하여 UHF대역(0.3${\sim}$3GHz)의 전자파 신호의 검출이 가능한 광대역 Rectangular 패치 안테나를 barrier coupler type UHF 센서에 적응 설계하였으며, Rectangular patch antenna를 배열(array) 했을 때의 특성들을 비교하였다. 이론 위해 상용화된 EM Simulator를 이용하여 센서의 방향성과 감도 특성을 검토하여 설계 및 제작하였다. 개발된 센서의 실제 특성을 분석하기 위해서 network analyzer로 센서의 특성을 분석하였고, 실규모의 GIS 챔버를 사용하여 다양한 결함에 대한 센서의 감도와 특성을 평가하였다. 본 연구의 결과로서 제작된 barrier coupler type UHF센서가 가스절연기기(GIS)의 부 부방전 신호를 검출할수 있음을 입증하였고, 광대역 외장형센서의 경우 patch antenna의 구조에 크게 상관하지 않음을 알 수 있었다. 향후에는 GIS 내장형 센서와 비교 연구론 통해 barrier coupler type 센서의 성능을 개선하고자 한다.