• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.10
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• pp.1021-1030
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• 2009

We propose optimization method of two-inductor loaded small loop antennas using simple genetic algorithm. To optimize the loop antennas for the RFID and the mobile phone band, we changed positions and values of the two inductors in the loop antenna. Visual basic was used to make genetic algorithm and to calculate fitness values by controlling the commercial EM software. The bandwidth of the optimized RFID loop antenna is 10 MHz at the center frequency of 922 MHz and that of the mobile phone antenna are 84 MHz and 266 MHz at the center frequency of 948 MHz(GSM band) and 1.81 GHz(DCS band), respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.7
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• pp.603-607
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• 2009

In this paper, a GPS antenna is designed by using metal film which can be attached on the case of battery without additional space for antenna in GPS band operation. The proposed metal film has a half-wavelength slot radiator. The slot radiator is fed by th electromagnetic field coupled from the GSM850/PCS band antenna. The proposed GPS antenna obtains about 20 MHz bandwidth(VSWR<3) which can cover entire GPS band. The antenna has an average gain of -3.8 dBi.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.76-78
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• 2011

In this paper, 0.8 GHz and 1.8 GHz dual-band antenna was designed for global system for mobile communications (GSM) and the Long Term Evolution (LTE) The proposed antenna was made using CST Microwave Studio 2009. My script antenna's substrate is Taconic TLY-5 and dielectric constant is 2,2 and has 1.0mm thickness with a compact design of the proposed antenna, Thus it shows that this proposed antenna can be used in Wireless Communication System.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.4
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• pp.477-483
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• 2008

The paper introduces mobile handset multi-band chip antenna to be used on meander line PIFA structure and parasite patch. The proposed antenna uses an FR-4 substrate. The top layer is consist of meander lines PIFA structure to implement GSM900 and is connected with each rad and meander line on the via-hole for maximize space efficiency. The middle layer is designed with the signal line and gap to implement a DCS and PCS bands, the bottom layer which is added to a parasite patch on the ground can be show an adjust of frequency and impedance character by the connection of the radiators of middle layer and coupling. The fabricated antenna with the dimension of $28{\times}6{\times}4\;mm^3$. The ground plane a dimension of $45{\times}90\;mm$, designed by a commercial software CST simulator. The experimental results show that the bandwidth for(VSWR<3) is 90($875{\sim}965$) MHz in GSM900 band operation and 380($1,670{\sim}2,050$) MHz in DCS, PCS band operation. The maximum gains of antenna are 0.25 dBi, 3.65 dBi and 3.3 dBi at resonance frequencies and it has omni-directional pattern practically.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.9
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• pp.1642-1649
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• 2007

The lumped element isolators with temperature compensation magnetic circuits were designed in this paper. Isolators for mobile repeater at each band of K-PCS, GSM1900, W-CDMA, WiBro were fabricated by using optimum parameters of EM simulation, Form the results of this study, first of all, insertion loss at K-PCS band was below 0.2 dB and return loss was over 25dB. The bandwidth in isolation 23dB was found 30 MHz. Secondly, the figures of both losses at GSM1900 were 0.25dB and 23dB, respectively. The measured bandwidth in isolation 30dB was 60MHz. Thirdly, the losses at W-CDMA band were 0.15dB and 25dB. The bandwidth in isolation 24.8dB was found 60Mhz. Finally, the figures of both losses at Wibro band were 0.25dB and 23dB, respectively. The measured bandwidth in isolation 22.1dB was 100Mhz. In addition, the results of measured IMD were shown from 76.4dBc to 80.1dBc.

• Journal of Advanced Navigation Technology
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• v.11 no.1
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• pp.72-78
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• 2007

In this paper, the wide-band monopole antenna with a parasitic element on the ground plane for application in Cellular, GSM and RFID mobile terminals such as the mobile phone or Personal Digital Assistant(PDA) phone is presented. The VSWR of the designed antenna is 2:1 over the frequency range of 820 MHz to 1040 MHz(bandwidth of 23.6 %). Therefore, the designed antenna can provide wide bandwidth covering the Cellular(824 MHz~894 MHz), RFID(908.5 MHz~914 MHz) and GSM(Tx:880 MHz~915 MHz, Rx:925 MHz~960 MHz). The radiation characteristics of the fabricated antenna were also studied. According to the measured radiation patterns, the maximum gains at 859 MHz and 911.25 MHz(center frequencies of the Cellualr and RFID bands) are -0.7 dBi and 0.16 dBi, respectively. The measured maximum gains of GSM bands are -0.48 dBi(897.5 MHz, the center frequency of Tx) and 1.69 dBi(942.5 MHz, the center frequency of Rx).

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.3
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• pp.48-55
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• 2008

This paper presents a design of a multi-band infernal antenna for mobile handsets which can cover the major mobile services such as WiBro/WiMAX mobile internet services and Media-FLO/S-DMB services. Using wideband monopole antenna structure, the proposed antenna obtains the wide bandwidth characteristic at high Sequency band to be applicable for new mobile services. Stacking meandered radiator on the wideband monopole radiator and obtaining the different current path and lenga on these stacked radiators, overall antenna volume is effectively reduced. The measured bandwidths (VSWR<3) of the proposed antenna is 270 MHz and 2032 MHz at low and high band, respectively. This antenna can effectively covers major wireless communication bands including Media-FLO, CDMA, GSM, GPS, DCS, PCS, UMTS, WiBro, WiMAX, and S-DMB.

• ETRI Journal
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• v.36 no.4
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• pp.690-693
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• 2014

Compact multi-band bandpass filters using quad-mode stub-loaded resonators are proposed in this letter. Firstly, a novel approach about the mode-splitting characteristics of the quadruple-mode resonator is investigated, which can provide dual-band behavior. Secondly, a quad-band filter is proposed and designed by cascading two quadruple-mode resonators; the upper one operates at 1.8/2.4 GHz (GSM- and WiMax-band) and the lower one at 1.57/2.1 GHz (GPS- and WCDMA-band). Finally, the proposed filters have been fabricated. Respectable agreement between simulation and measurement verifies the validity of this design methodology.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.427-431
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• 2007

Applications in present-day mobile communication systems particularly require miniaturized dimensions and low-profiles of antenna in order to meet the mobile units. Thus, size reductions and bandwidth enhancements are becoming crucial design considerations for practical applications of microstrip antennas. The motivation of further experiments have been stepped to follow those studies for achieving compact and broadband, even multiplied operation modes, which are greatly increased with much attentions recently. To obtain broadband, single-feed, circularly polarized characteristics of microstrip antennas, a design with feed-line ought to be a factor of two. Usually, diagonally balanced-line feeds with hybrid coupler are employed to attain circular polarizations. We firstly formulated DGS (Defected Ground Structures) based operation principles of the entire microstrip components and therefore were able to derive impedance variance of feed-lines. After verifying corresponding experimental results, we targeted the frequency bands of UHF RFID (Ultra High Frequency Radio Frequency IDentification) and approximately of 0.4-2.4GHz have exhibited remarkable two resonance amplitudes as a dual band antenna. Our secondary researches were aimed to design quad band microstrip antenna which represents four resonance characteristics within the identical frequency bands as well. Microstrip patch has been meandered to lengthen the electrical paths, and the other design criteria with respecting physical parameters including radiation patterns and impedance bandwidths measurements will be described for verification. Advisable applications of these antennas can be GSM850, GSM900, GPS (L1-1575 and L2-1227) and UMTS-2110 of cellular systems, which extremely desire multiband and minimum size.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.6
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• pp.984-989
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• 2008

In this paper, we will design a 800MHz broadband antenna after a problem of the narrow bandwidth is improved. This multiple band antenna unifies the CDMA(Code Division Multiple Access), GSM(Global System for Mobile Telecommunication) and TRS(Trunked Radio System) band in the UHF band, and then it is possible at the shore base station or repeater as the commercial use. It used the duplex resonance effect it had the L-shared feeding structure which adds the U-slot. And it improved profit using stack structure. It was measured that the frequency bandwidth of the designed antenna which is planed $792{\sim}1040MHz$ with 248MHz(33%). And the antenna gain is 9.4dBi, 3dB beam width $60^{\circ}$ in radiation pattern.