• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.8
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• pp.1159-1163
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• 2012

In this paper, a new method is suggested to reduce the size of a wide-band array antenna. The power-divider for the feeding structure is made compact as ${\lambda}/8$ with the help of a novel Metamaterial UWB bandpass filter. This power divider is clearly different from others in that the proposed design uses microstrip structured Composite Right and Left-Handed (CRLH) filters, while others use two dielectric layers or long tapered transmission lines. In order to validate the proposed design method, the circuit and full-wave simulated results of the power divider with the Metamaterial UWB filters are compared to each other, and the Metamaterial properties of the structure are shown with the electric field at the ZOR and dispersion diagram. Furthermore, the antenna performance of the fabricated antenna with the power divider is measured and compared with the prediction. Also, the size reduction effect by the proposed scheme is addressed.

• Journal of information and communication convergence engineering
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• v.6 no.1
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• pp.51-54
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• 2008

The defected ground structure (DGS) for microstrip structure can be used to protect analog/RF signal from SSN interference of digital circuits on PCB with common ground. However, the basic DGS gives rise to undesired emissions that may interfere with nearby circuitry due to the ground discontinuity. In this paper, we have proposed the modified structure, Corrugated DGS and the method to reduce the radiation by adding the lumped resistor on the proposed Corrugated DGS.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.350-353
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• 2003

In this paper, we designed and implemented a 10dB directional coupler with high directivity using branch line structure. The characteristic impedance of parallel branch line for 10 dB directional coupler is about 150 $\Omega$. To realize high characteristic impedance in microstrip line, we used the coupled line structure. The directional coupler were implemental and measured. The measured results show that the directivity is high than 24 dB.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.779-783
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• 2012

In this paper, we studied the design and fabrication of $2{\times}2$ array-type microstrip patch antenna to be used in wireless communication systems operating at around 5GHz band. To obtain wide bandwidth and high gain, antenna parameters such as patch size, inter patch space are simulated by HFSS(High Frequency Structure Simulator). From these parameters, the $2{\times}2$ array-type microstrip patch antenna is fabricated using FR-4 substrate. The measured results of the antenna are as follows: The center frequency of 5.06GHz, insertion loss of -44dB, bandwidth of 200MHz, and VWSR of 1.1.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.1
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• pp.44-52
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• 2014

In this study, the influence of the near field, far field and radiation directivity of microstrip patch antenna when is used mushroom EBG(Electromagnetic Band Gap) as ground is investigated. Using characteristic of dispersion diagram of mushroom EBG, we calculated forbidden band(2.36GHz-2.85GHz) given mushroom type EBG microstrip antenna(2.45GHz) having 2-layer EBG that is operating within forbidden band. In oder to conform performance enhancemen of antenna using EBG ground, we have compared with the antenna using PEC(Perfect Electric Conductor) ground. We could know about 2.74dB increment of the radiation directivity, because EBG can suppress surface wave that is generated at interfaces of the dielectrics-conductor.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.1
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• pp.79-85
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• 1999

The propagation properties of the high speed pulse signal in time domain using the equivalent circuits for the analysis by SPICE on the coupled microstrip lines are investigated. In this paper, the SPICE program is used for the crosstalk analysis on the coupled microstrip lines. The results of crosstalk of coupled microstrip lines compared to one by Branin and FDTD method. And the near-end and far-end crosstalk on coupled lines are analyzed for the square pulse and trapezoidal pulse. The results of this paper are apply To the determination for the geometric structure and the frequency of signal pulse in design of MIC and MMIC by the CAD program.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.9
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• pp.1-5
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• 1999

In this paper, we proposed a novel branch-line coupler using filp-chip technology. The proposed coupler consists of CPW and inverted microstrip. The CPW is on the GaAs flip-chip substrate, and the inverted microstrip is on the alumina main substrate. The ground plane of the CPW is used as a ground plane of the inverted microstrip. And both the transmission lines are connected by solder bump with each other. The characteristics of thisstructure was calculated by FDTD method. The S21, S31 are -3dB and the phase difference is $90^{\circ}$. The calculated characteristics are the same as those of the regular branch-line coupler. This structure can be applied for various kinds of devices using flipchip technology.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.7
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• pp.644-652
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• 2004

In this paper, we designed a cascaded microstrip lowpass filter using the lowpass filters previously proposed. The previously proposed lowpass filters have a ultra-wide stopband and prominent cutoff sharpness using the combined characteristics of slot and microstrip open stub, respectively, and they are catagorized into 2 types by the method that determining their passband characteristics. The first type is determined its passband characteristics by open stub characteristics and the second is by slot characteristics. By cascading these structures with impedance adjustment of each element, the deeper out-of-band rejection and the sharper skirt response were achieved. The fabricated cascaded lowpass filters have -3㏈ cutoff frequencies at 1.035㎓ and 1.286㎓ respectively and -20㏈ stopband is over 20㎓ for both structures.

• Journal of Korea Society of Industrial Information Systems
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• v.9 no.2
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• pp.74-80
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• 2004

This paper presents analysis and design for Microstrip antennas using FEM (Finite Element Method). For the miniaturization of the antennas, dielectric substrate (ε/sub r/=4.6) and rectangular patch structure are used. The proposed Microstrip antennas are simulated using commercial simulator (HFSS). The results of the simulation are presented and compared with characteristics of each array type. Especial, the proposed antennas can be applied to the design of various communication systems for 2.4 GHz band.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.55-56
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• 2018

In this paper, a method for analyzing the dielectric constant of a planar substrate is proposed. To this end, a band-stop filter was created by adding a H-shaped resonant aperture to the ground plane of a microstrip transmission line. A planar substrate of 2 mm thickness was placed behind the ground plane of the microstrip transmission line and the change of the resonant frequency with the change of the dielectric constant of the substrate was investigated. It can be seen that the change ratio of the frequency to the reference resonant frequency is larger than that of the conventional complementary split ring resonator structure.