• Journal of electromagnetic engineering and science
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• v.12 no.4
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• pp.247-253
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• 2012

This study presents a new, simple method for improving the front-to-back (F/B) ratio of a microstrip patch antenna. The back radiation of the microstrip patch antenna is reduced by removing some metallic parts around the ground plane and placing a new soft-surface configuration, consisting of an array of stand-up split-ring resonators on a bare dielectric substrate near the two ground plane edges. Compared to the F/B ratio of a conventional microstrip patch antenna with a full ground plane of the same size, our proposed microstrip patch antenna experimentally achieves an improved F/B ratio of 9.6 dB.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.397-400
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• 2001

In this paper, to improve bandwidth of microstrip antenna, we discussed the patch structure using Aperture Stacked Patch. To provid PCS service and IMT-2000 service simultaneous, a microstrip patch antenna needs impedance bandwidth of 22%. But typical microstrip patch antennas have impedance bandwidth of 3∼6%. To analyze characteristics of microstrip pach antenna, we used Ensemble of commercial software. The microsrtip patch antenna was designed and fabricated, tuned. We get following results; 650MHz(33%) of impedance bandwidth for VSWR 1.5. The measured gain of ASP microstrip antenna is 6.94dBi.

• The Journal of the Acoustical Society of Korea
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• v.13 no.1E
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• pp.5-10
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• 1994

It is obtained the general expessions of the numerical method are applied for the TEM-mode analysis of multu-layer multi-coupled microstrip lines, In this paper, coupled microstrip are replaced by three-coupled microstrip lines in special aplications. Three-layer versions of three-coupled microstrip lines are specially attactive because of the additional flexibilities offered by three-layer configuration. This structure can be used for obtaining large capacitance and preventing coupling among microstrip lines in filter and coupler. Sappihre is chosen for anisotropic substrates material. The permittivity parallel to the optical axis is higher than the permittivity in the plane perpendicular to this axis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3A
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• pp.424-429
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• 2000

In this paper, the characteristics of the asymmetric coupled microstrip(ACM) lines with finite metalization thickness are investigated using the quasi-static analysis in the multilayered structure. By mode-matching method as the quasi-static analysis. the characteristic impedances and effective dielectric constants in ACM lines are obtained as a function of metalization thickness. The numerical results show that the propagation characteristics of ACM lines in the single and multilayered structure will be changed by the variation of metalization thickness.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.8
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• pp.1740-1746
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• 1997

In this paper, a waveguide-fed slot-coupled microstrip antenna is proposed as enhanced feeding structure of microstrip antenna and an analysis is presented. The presence of dielectric substrate between a stripand a slot is explicitly taken into account in this analysis. The evaluation of the antenna characteristics is carried out using the method of mements and the spectral domain approach in terms of the electric current distribution on the strip and the magnetic current distribution on the slot. From the results, we can conclude that the proposed structure is adequate for array antennas, due to ease of mass porduction and enhanced anteena performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.1
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• pp.54-59
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• 2019

In this paper, we report on the waveguide-to-microstrip transition with an inline structure for the millimeter band. The waveguide-to-microstrip transition comprises a probe, an inductive line, a ${\lambda}/4$ impedance transformer, and a 50-ohm microstrip line. For the transition design, we optimized the characteristic impedances and lengths of the component parts. The fabricated transition exhibits an insertion loss of 2.1 dB and an input/output return loss of below 13 dB at a millimeter band frequency of 94 GHz.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5447-5451
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• 2012

This paper presents a pattern-switchable microstrip patch antenna with loop structure. The loop structure for switchable radiation beam pattern is connected with feeding line of the microstrip patch antenna. As changing switch on/off state, the radiation beam pattern can be changed. The target frequency is 2.4 GHz and maximum radiation gain is 3.2dBi. The proposed antenna is useful for diversity antenna and smart antenna in modern wireless communication including MIMO (Multi-Input Multi-Output) and WLAN system. The sizes of the rectangular patch and the ground plane are $28mm{\times}28mm$ and $40mm{\times}50mm$, respectively. The simulation and experimental results show that the antenna radiation pattern can be changed with switch on/off configuration.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.9-15
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• 2011

The microstrip reflectarray antenna is rapidly becoming an attractive alternative solution to the traditional parabolic reflector antenna. However, the bandwidth of the microstrip reflectarray using the single layer structure is very narrow. To obtain wide bandwidth characteristic, the microstrip reflectarray using the multi-layer structure has been used, but it has some disadvantages such as high cost and complicated design. In this paper, to obtain low cost and wide bandwidth, the microstrip reflectarray antenna composed of square patch with two U-slots using the single-layer structure is proposed. The proposed antenna demonstrate radiation efficiency closed to 55.5 % and 1 dB gain bandwidth over 14 % at 12.5 GHz.

• Transactions on Electrical and Electronic Materials
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• v.16 no.1
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• pp.10-15
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• 2015

A thin-film transmission line (TFTL) employing a microstrip line/coplanar waveguide (ML/CPW) was fabricated on a silicon substrate for application to a miniaturized on-chip RF component, and the RF characteristics of the device with the proposed structure were investigated. The TFTL employing a ML/CPW composite structure exhibited a shorter wavelength than that of a conventional coplanar waveguide and that of a thin-film microstrip line. When the TFTL with the proposed structure was fabricated to have a length of ${\lambda}/8$, it showed a loss of less than 1.12 dB at up to 30 GHz. The improvement in the periodic capacitance of the TFTL caused for the propagation constant, ${\beta}$, and the effective permittivity, ${\varepsilon}_{eff}$, to have values higher than those of a device with only a conventional coplanar waveguide and a thin film microstrip line. The TFTL with the proposed structure showed a ${\beta}$ of 0.53~2.96 rad/mm and an ${\varepsilon}_{eff}$ of 22.3~25.3 when operating from 5 to 30 GHz. A highly miniaturized impedance transformer was fabricated on a silicon substrate using the proposed TFTL for application to a low-impedance transformation for broadband. The size of the impedance transformer was 0.01 mm2, which is only 1.04% of the size of a transformer fabricated using a conventional coplanar waveguide on a silicon substrate. The impedance transformer showed excellent RF performance for broadband.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.4
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• pp.401-406
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• 2002

A microstrip circuit with multilayer structure is applied variously in the MMIC. For effective transmission between microstrip lines with different dielectric height, it is need to analyze and to induce accurately the equivalent circuit in 3 dimensional stepped discontinuous microstrip line. In this paper, by using the S parameters obtained by FDTD numerical method and measurement, T equivalent circuit and its element values were induced. And the analyzed and measured results showed good agreement in 1 ∼5 ㎓ range.