• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.17-23
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• 2021

In the present study, a more compact dual-band slot antenna is newly proposed for Wi-Fi application. The proposed antenna is composed of rectangular two stepped slot with open end which can generate standing wave resonance at dual frequency bands and L-type microstrip feed line. The measured impedance bandwidths are 50 MHz(2.412 ~ 2.470 GHz) at low frequency band and 452 MHz(5.451 ~ 5.903 GHz) at high frequency band respectiviely. Furthermore its size of 14 × 21 mm² is reduced by 30% compared to the size of 20 × 21 mm² of a conventional similar compact slot antenna. It has the omni-directional radiation pattern characteristics of a typical dipole antenna on the H-Plane, so it is suitable for commercial wireless network applications such as Wi-Fi.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.9 s.100
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• pp.872-882
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• 2005

In this paper, we examined the operating principle of a passive tag antenna for RFID system in UHF band. Based on the study, we proposed a novel RFID tag antenna which adopts the inductively coupled feeding structure to match antenna impedance to a capacitively loaded commercial tag chip. The proposed tag antenna consists of microstrip lines on a thin PET substrate for low-cost fabrication. The detail structure of the tag antenna were optimized using a full electromagnetic wave simulator of IE3D in conjunction with a Pareto genetic algorithm and the size of the tag antenna can be reduced up to kr=0.27($2 cm^2$). We built some sample antennas and measured the antenna characteristics such as a return loss, an efficiency, and radiation patterns. The readable range of the tag antenna with a commercial RFID system showed about 1 to 3 m.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.63-64
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• 2013

In this paper, a design method for a dual dipole antenna for an operation in the frequency band of 470-806 MHz for indoor digital TV (DTV) is studied. The proposed antenna is composed of two planar dipoles connected by parallel strip line, and the antenna is fed by a microstrip line. By employing different lengths of dipoles, a broadband characteristics is obtained, and the antenna is size-reduced by bending both ends of the longer dipole. The effects of each parameters on the antenna performance are examined by simulation, and the parameters are optimized for the DTV use. A prototype antenna with optimized parameters for the indoor DTV use is fabricated on an FR4 substrate and tested experimentally. The experimental results show that the frequency band for a VSWR < 2 ranges 458-864 MHz (61.4%, bandwidth 406 MHz, 1.89:1), and it corresponds fairly well with the simulated band 448-868 MHz (63.8%, bandwidth 420 MHz, 1.94:1).

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2351-2358
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• 2014

In this paper, a design method for a compact CPW-fed slot antenna using SRRs is studied. The structure of the proposed slot antenna is a rectangular slot antenna loaded with SRR conductors inside the slot to reduce the antenna size. Optimal design parameters are obtained by analyzing the effects of the gap between the SRR conductors and slot, and the width of the SRR conductors on the input VSWR characteristic. The optimized compact slot antenna operating at 2.45 GHz band is fabricated on an FR4 substrate with a dimension of 36 mm by 30 mm. The length of the proposed compact slot antenna is reduced to 14.3% compared to that of a conventional rectangular slot antenna. Experiment results show that the antenna has a desired impedance characteristic with a frequency band of 2.4-2.49 GHz for a VSWR < 2, and measured gain of 2.3 dBi at 2.45 GHz.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.157-158
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• 2014

In this paper, a design method for a compact CPW-fed slot antenna using SRRs(split-ring resonators) is studied. The structure of the proposed slot antenna is a rectangular slot antenna loaded with SRR conductors inside the slot to reduce the antenna size. Optimal design parameters are obtained by analyzing the effects of the gap between the SRR conductors and slot, and the width of the SRR conductors on the input reflection coefficient characteristic. The optimized compact slot antenna operating at 2.45 GHz band is fabricated on an FR4 substrate with a dimension of 36 mm by 30 mm. The length of the proposed compact slot antenna is reduced by 14.3% compared to that of a conventional rectangular slot antenna. Experiment results show that the antenna has a desired impedance characteristic with a frequency band of 2.4-2.49 GHz for a VSWR < 2.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.450-453
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• 2003

In this paper, the miniaturization of linear polarization microstrip patch antenna is studied by attached Irises near the square linear polarization microstrip patch antenna which are induced the increase of current path. Microstrip patch antenna having the Irises is designed and fabricated at the resonant frequency of 1.575 GHz. The result is like that the resonant length of patch is reduced 41.5 mm which correspond to 50.9 % of that of plane type(81.5mm). The return loss is -28.5 dBd and -10 dB bandwidth is 103 MHz( 6.5 %). And as the radiation pattern is broad through the size reduction of patch, the gain is 5.9 dBd and -3 dB beamwidth of E-plane is $111.9^{\circ}$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11B
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• pp.1620-1627
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• 2001

In this paper, a broadband microstrip antenna for PCS and IMT-2000 service is designed. To obtain the broadband characteristics of an antenna, we utilized the multi-layered structure composed of two foam material layers, parasitic element and aperture coupled feeding network. The broadband characteristic is obtained by changing the size of parasitic element and the height of foam materials. In addition to that, the usage of metal layer at the distance of λ/4 from feed-line, back radiation is reduced. The bandwidth of a single element for VSWR less than 1.3 is about 550MHz. The bandwidth of a designed 1$\times$4 array antenna for VSWR less than 1.3 is about 460MHz. The gain of a designed array antenna is about 11.15∼12.15dBi and the front-to-back ratio is about 30dB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.10
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• pp.2245-2251
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• 2013

In this paper, a design of a compact series-fed dipole pair(SDP) antenna with end-loaded rectangular patches is presented. In order to reduce the lateral size of a conventional SDP antenna, rectangular patches are end-loaded to the two dipole elements of the SDP antenna and a grooved ground plane is used by adding a patch at both ends of the ground plane. The effects of varying the length and width of the rectangular patches on the antenna performance such as input reflection coefficient are investigated. An optimized compact SDP antenna covering a frequency band ranging from 1.7 GHz to 2.7 GHz is designed and fabricated on an FR4 substrate. The total width of the fabricated prototype of the proposed antenna is reduced by approximately 14.3% compared to the conventional SDP antenna. Experimental results show that the antenna presents a 48.7% bandwidth in the range of 1.68-2.76 GHz and a stable gain of 5.6-6.0 dBi with minimal degradation. Moreover, a front-to-back ratio is improved by about 0.7 to 7.4 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.8
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• pp.806-812
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• 2009

In this paper, the omnidirectional circularly polarized(CP) antenna using arc-shaped mushroom structure with curved branch is proposed. To obtain a vertical polarization and an omnidirectional radiation pattern, the CP antenna uses zeroth-order resonance(ZOR) mode of composite right and left handed(CRLH) transmission line. The horizontal polarization is achieved by the curved branches. Also, the spacing between curved branch and arc-shaped mushroom structure gives the $90^{\circ}$ phase difference between vortical and horizontal polarization. The proposed antenna, therefore, has an omnidirectional CP radiation pattern In the azimuthal plane. The electrical size of the proposed antenna is reduced by 38%, compared with that of the previously presented omnidirectional CP antenna. In addition, the CP antenna is simply designed without $90^{\circ}$ phase shifter and dual feed line. The proposed antenna uses a Bazooka balun for good impedance matching and radiation pattern. To improve 3 dB axial ratio in XY plane, the designed antenna is optimized. After optimization, the measured 3 dB axial ratio in XY plane is observed in $86{\sim}282^{\circ}$.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.133-139
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• 2012

Currently, we are living in the world of invisible radio waves with a variety of frequencies. As today's society is rapidly changing to an era of wireless communication, the importances of antenna(especially, small patch antenna) are increasing according to the coming of wireless mobile communication society. In this paper, we design a small patch antenna which can support the functions of DMB and GPS through devices like cellular phone. The main feature and contribution of the designed patch antenna are as follows. First, the patch antenna is designed by HFSS and the ceramic materials for the patch antenna is utilized. Second, we obtain the patch antenna with reduced size and increased profit of reception, and the designed patch antenna can be applied for small devices.