• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.12 s.103
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• pp.1213-1221
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• 2005

In this paper, dual-polarized antenna for UHF RFID reader has been described. Feeding network and antenna structure have been designed, such that both port isolation between transmitting and receiving port and cross-polarization be maximized, and overall antenna size be minimized as well. In addition, sequentially rotated feeding scheme has been adopted to secure axial ratio bandwidth in the circular polarization. Test results show 2.35 dBi antenna gain in 900 to 928 MHz frequency range and 150 MHz axial ratio bandwidth, respectively. And, the proposed antenna has a port isolation of -40 to -38 dB and a cross-polarization of -40 to -30 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.6
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• pp.535-543
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• 2009

This paper describes a design for RFID(Radio Frequency Identification) tag antenna using license plate attached the vehicle bumper in 900 MHz band. The proposed tag antenna size which is located on upper center position of a vehicle license plate is 162.5${\times}$40${\times}$1 mm$^3$. A resonant frequency of design antenna and the bandwidth which has return loss of -10 dB below are 900 MHz and about 720 MHz(640${\sim}$1,360 MHz), respectively. The commercial chip impedance considered on design was 16- j131 ${\Omega}$ and the complex conjugate impedance of chip was used as input impedance of tag antenna. The measured return loss and radiation pattern were agreed well with the calculated results. The measured readable range of the proposed tag antenna designed on only the vehicle license plate was 11.5 m. Moreover, its range of the fabricated tag antenna that the license plate and the vehicle bumper were fixed by volt and nut was observed 10.4 m. These measured readable range showed about 5 m above far distance more than the average readable range of commercial tag antenna.

• Journal of information and communication convergence engineering
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• v.9 no.1
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• pp.16-20
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• 2011

In this paper, we designed and implemented an internal multi-band folded monopole antenna for mobile handset. The proposed antenna covers Global System for Mobile Communications (GSM900: 880~960 MHz), Digital Communications System (DCS: 1710~1880 MHz), US-Personal Communications Service (US-PCS: 1850~1990 MHz), Bluetooth(2400~2484 MHz), WiMAX(3400~3600 MHz), and Wireless Local Area Network (WLAN: 5150~5350 MHz, 5725~5875 MHz) band for Voltage Standing Wave Ratio $(VSWR)\;{\le}\; 3$. The measured peak gains of the implemented antenna are -1.78dBi at 920MHz, 2.72dBi at 1795MHz, 2.25dBi at 1920MHz, 2.34dBi at 2442MHz, 2.11 dBi at 3550MHz, and 2.04 dBi at 5250MHz.

• Journal of IKEEE
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• v.15 no.4
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• pp.339-344
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• 2011

In this paper, we proposed an internal multi-band monopole antenna for mobile phone that can be used for smart phones. The proposed antenna has a small volume of $38{\times}8.5{\times}5\;mm^3$, ground size is $100{\times}60\;mm^2$, and covers the GSM900 (Global System for Mobile communications : 880-960 MHz), DCS (Digital Communications System : 1710-1880 MHz), K-PCS (Korea-Personal Communications Service : 1750-1870 MHz), US-PCS (US Personal Communications Service : 1850-1990 MHz), Bluetooth (2400-2483 MHz), Wibro (2300-2390 MHz) and WLAN (Wireless Local Area Network : 2400-2483.5 MHz) bands. The measured peak gains of the implemented antenna are 1.15 dBi at 920 MHz, 3.58 dBi at 1795 MHz, 3.46 dBi at 1810 MHz, 2.91 dBi at 1920 MHz, 5.18 dBi at 2345 MHz, 3.37 dBi at 2442 MHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.706-713
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• 2010

In this paper, the small loop antenna with a parasitic loop structure for penta-band mobile phone application is proposed. This antenna is composed of a feed monopole, a radiating loop antenna with a parasitic loop structure and an additional radiating element. The antenna is printed on the very thin flexible substrate to mount on the dielectric carrier with a volume of 40 mm$\times$11 mm$\times$3 mm. The bandwidth of the proposed antenna is 402 MHz(773~1,175 MHz) for low band and 583 MHz(1,622~2,205 MHz) for high band. As a result, the proposed antenna covers the five bands of GSM850, GSM900, DCS1800, PCS1,900 and WCDMA for a 3:1 VSWR. Moreover, the radiation pattern, gain and efficiency are appropriate for mobile handset. Therefore, this antenna is suitable for small sized multi-band mobile handset applications.

• Journal of Navigation and Port Research
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• v.32 no.10
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• pp.793-798
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• 2008

This paper presents a design of RFID(Radio Frequency Identification} tag antenna which has high sensitivity for car side mirror. A proposed tag antenna ($154\;mm{\times}66\;mm{\times}1;mm$) resonants at 900 MHz and has a wide bandwidth of 690 MHz($490\;MHz{\sim}1180\;MHz$). The measured gain and readable range of tag antenna are 5.8 dBd and 10 m, respectively. Radiation pattern and readable range of proposed tag antenna located on inside of a side mirror including a car body are measured at anechoic chamber. It has been confirmed that the readable range in the vicinity of $90^{\circ}$ has been expanded about 1.5 m by comparison with one of proposed tag antenna without of car body. Good performance of the proposed tag antenna was observed and proved by comparison of measured results of commercial tag antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.2
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• pp.154-160
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• 2009

This paper describes a wide bandwidth RFID tag antenna design for protection of connection part between chip and antenna. A proposed tag antenna size, a resonant frequency and bandwidth are $53{\times}10{\times}1\;mm$, 900 MHz and 800 MHz($500{\sim}1,300\;MHz$) at -10 dB below, respectively. The dielectric materials with different relative permittivity such as polyethylene, glass and silicon were applied for protection of connection part between the proposed antenna and chip on the way of whole and partial housing. The measured return loss and radiation pattern agreed well with the calculation results. The read range of the proposed tag antenna without any housing and of tag antenna with housing covered over all by silicon with 3 mm thickness were observed about 5 m and 4 m, respectively.

• Journal of Navigation and Port Research
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• v.33 no.1
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• pp.51-56
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• 2009

This paper presents the design of high sensitive/broadband tag antenna for Radio Frequency Identification (RFID) in Ultra High Frequency(UHF) band. A proposed tag antenna size is $60\;mm\;{\times}\;10\;mm\;{\times}\;1\;mm$. The resonant frequency is 910MHz and bandwidth is about 900 MHz at -10 dB below. The measured return loss and directional pattern have been confirmed a good agreement with the calculation results. The read range of proposed tag antenna with chip is observed about 6.5 m and proposed tag antenna has been observed an average 0.5 m for more than read range of the commercial tag antenna.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.3
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• pp.17-24
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• 2013

In this paper, the measurement data is analyzed and channel characteristics are derived through MIMO Channel measurements at 781MHz considering antenna correlation. 781MHz frequency band currently operates the DTV system, however, it will be allocated new mobile communication frequency band. The channel characteristics at 781MHz seem to be similar existing mobile communication system at 900MHz but quite a different part of the existing research has demonstrated. In addition, the signal procedure of the channel characteristics, considering the correlation of the antenna, for a more accurate prediction research is needed. To avoid interference with Korean DTV broadcasting, we measured channel characteristics in urban areas of Jeju island by channel sounder and $4{\times}4$ antenna. Channel characteristics with antenna correlation were derived based on the measured data in the urban area.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.4
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• pp.411-417
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• 2008

This paper presents the miniaturization of circularly polarized microstrip patch antenna for UHF-band RFID portable reader. The proposed antenna has a group of four I-slots on a conventional corner-truncated square microstrip patch and it is shown that the antenna size is reduced compared to the antenna without I-slots. A 76 mm by 76 mm small antenna with four I-slots is fabricated with 6.4 mm thick FR4 substrate and its 10 dB return loss bandwidth, the gain and the axial ratio are measured to be $938{\sim}975\;MHz$, $-0.88{\sim}-2\;dBi$, and $3.27{\sim}13.21\;dB$ within the 10 dB return loss bandwidth, respectively.