• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.11
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• pp.951-959
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• 2015

Ground radiation antenna in mobile devices is becoming an issue for satisfying both miniaturization and high performance. Ground radiation antenna controls the characteristic mode of the ground plane and couples this mode with the ground radiation antenna, thereby having good radiation performance. In this paper, the characteristic mode theory and applications of ground radiation antenna will be introduced. The operating mechanism of single band, wideband and dual-band ground radiation antennas are studied.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.559-562
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• 2004

The $high-T_c$ Superconducting(HTS) antenna which consists of "H" type resonator has the benefits for the miniaturization of antenna in comparison with the microstrip antenna of the similar dimension. To fabricate the "H" type antenna HTS $YBa_2Cu_3O_{7-x}$(YBCO) thin films were deposited on MgO substrates using rf-magnetron sputtering. Standard etching processes were performed for the patterning of the "H" type antenna. For comparison between normal conducting antennas and superconducting antennas, the gold antennas with the same dimension were also fabricated. An aperture coupling was used for impedance matching between $50\Omega$ feed line and HTS radiating patch. The diverse experimental results were reported in terms of the resonant frequency, the return loss and the characteristics impedance. The "H" type superconducting antenna showed the performance of 1.36 in SWR, 24 % in efficiency, and 14.6 dB in the return loss superior to the normal conducting counterpart.

• Transactions on Electrical and Electronic Materials
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• v.18 no.2
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• pp.119-123
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• 2017

This paper presents a unique and miniaturized dual-band coplanar waveguide (CPW-fed) antenna for modern wireless communication. A new technique of using a modified ground structure (MGS) and frequency shifting strips (FSS) has been employed in the design to achieve dual-frequency operation. The proposed antenna generates two separate impedance bandwidths and covers the minimum required frequency bands of GSM 1800, GSM 1900, and Wi-Fi/WLAN 5 GHz. The proposed antenna is relatively small ($17{\times}20mm^2$) and operates over frequency ranges 1.51~2.06 and 4.43~6.70 GHz. The designed antenna was simulated using Ansoft HFSS, a FEM based simulator, and antenna characteristics, such as reflection coefficient, gain, radiation efficiency, radiation pattern, impedance bandwidth, VSWR, surface current, and electric field distributions, are reported in this paper. The effect of the antenna's key structural parameters on its performance is also analyzed.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.3
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• pp.62-72
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• 2022

In this study, a miniaturized GPS band(L₁ : 1.575 GHz) antenna that can be mounted on a small drone is proposed. The miniaturization was designed by applying the perturbation method based on the λ/4 microstrip antenna and lengthening the current path at the edge of the patch. The miniaturized antenna was fabricatred such that it could be attached to the surface of styrofoam(ε_r=1.06, t=10 mm) having a size of 10 mm × 9 mm × 10 mm (0.05 λ × 0.05 λ × 0.05 λ). The thickness and length of the feeding line and the spacing between short stubs were adjusted for impedance matching. S₁₁ was found to be -18.8 dB at the center frequency of the fabricated antenna, 1.575 GHz. The radiation pattern measurement results show that the maximum gain of E_θ is 1.87 dBi in 0 directions in the xz-plane, and that E_θ is an omnidirectional characteristic with an average gain of -1.7 dBi in the yz-plane. It was found that the antenna can be used as an ultra-small microstrip antenna, which can be mounted on a small dron for GPS, and is capable of preserving a reduction ratio of 98.8% as compared to a λ/2 microstrip patch antenna.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.7
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• pp.282-287
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• 2003

″H″ type resonator has the advantage for the miniaturization of high-T7 superconducting (HTS) microstrip antenna in comparison with the conventional microstrip antenna such as rectangular type or circular type. In this paper we designed miniaturized HTS antennas using this "H"-type resonator and reported the characteristics of our antennas including return loss, bandwidth, radiation patterns, efficiency and so on. To fabricate the "H" type antenna, HTS YBa$_2$Cu$_3$$O_{7-x}$ (YBCO) thin films were deposited on MgO substrates using rf-magnetron sputtering. For comparison between normal conducting antennas and superconducting antennas, the gold antennas with the same dimension were also fabricated. An aperture coupling was used for impedance matching between 50 $\Omega$ feed line and HTS radiating patch. The ″H" type superconducting antenna showed the performance of 1.38 in SWR, 26 % in efficiency, and 13.8 dB in the return loss superior to the normal conducting counterpart.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.685-688
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• 2008

Planar antennas are very efficient for the use of the out-door data transmission applications due to their low-profile characteristics. But the size of the antenna in UHF band blocks the practical usage. In this paper, a miniaturized planar antenna is investigated for the application of AMR system in UHF band. The designed antenna is fabricated in the form of the microstrip patch on the FR-4 substrate. The miniaturization is achieved by slot-loading on the patch. First, effects of simple slots on the size reduction are analyzed, followed by the design using more complex slots resulting in the reduction ratio of 37.9% in 425.6 MHz and bandwidth of 3.8 MHz. The effect of epoxy coating for the protection is also investigated.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.6
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• pp.979-983
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• 2008

Planar antennas are very efficient for the use of the out-door data transmission applications due to their low-profile characteristics. But the size of the antenna in UHF band blocks the practical usage. In this paper, a miniaturized planar antenna is investigated for the application of AMR system in UHF band. The designed antenna is fabricated in the form of the microstrip patch on the FR-4 substrate. The miniaturization is achieved by slot-loading on the patch. First, effects of simple slots on the size reduction are analyzed, followed by the design using more complex slots resulting in the reduction ratio of 37.9% in 425.6 MHz and bandwidth of 3.8 MHz. The effort of epoxy coating for the protection is also investigated.

• ETRI Journal
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• v.33 no.2
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• pp.291-294
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• 2011

This letter proposes an open-ended waveguide antenna with a single split-ring resonator. In contrast to the waveguide antennas incorporating multiple rings reported in a previous study, which exhibited narrow bandwidth, the proposed antenna uses only one ring to achieve broader bandwidth while keeping the aperture small. A single ring has a relatively low quality factor compared to multiple rings. The simulated and measured fractional bandwidth was 4.13% and 4.03%, respectively, which is much broader than the fractional bandwidth of about 1% demonstrated in a previous study. This simple technique can be used in many applications that require small apertures including near-field probes and array elements.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.815-820
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• 2007

In this paper, a small internal antenna for dual-band(RFID, PCS) applications is presented. The proposed antenna is a basic PIFA type and has a deformed ground plane under the main radiator. The modified ground plane is spreading the surface current and the antenna miniaturization can be achieved due to the coupling effect. The antenna is manufactured according to the simulation results and the resonance frequency move to low frequency band by 150MHz. And the surface current on the radiator and ground plane is evenly distributed so our suggested antenna can be used for better SAR and HAC performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.2
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• pp.145-149
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• 2006

UHF band omnidirectional antennas for RFID tag were designed. Crossed loaded dipole and bended dipole were applied to be designed for both miniaturization and omnidirectional radiation pattern. By suppling 90 degrees phase difference between crossed dipoles, omnidirectional E-plane patterns can be obtained. -10 dB reflection coefficients of 3 types dipole antenna which have designed under conjugate matched with input impedance of chip were shown as 670-1,050 MHz, 700-1,250 MHz and 600-1,020 MHz, respectively, and also shown that all antenna have omnidirectional radiation pattern both E and H plane.