• Journal of electromagnetic engineering and science
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• 제18권2호
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• pp.101-107
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• 2018

The impedance bandwidth and radiation characteristics of an aperture-coupled microstrip line-fed patch antenna (ACMPA) with a high permittivity (${\varepsilon}_r=10$) feed substrate suitable for integration with a monolithic microwave integrated circuit (MMIC) are investigated for various feed substrate thicknesses through an experiment and computer simulation. The impedance bandwidth of an ACMPA with a high permittivity feed substrate increases as the feed substrate thickness decreases. Furthermore, the front-to-back ratio of an ACMPA with a high permittivity feed substrate increases and the cross-polarization level decreases as the feed substrate thickness decreases. As the impedance bandwidth of an ACMPA with a high permittivity feed substrate increases and its radiation characteristics improve as the feed substrate thickness decreases, the ACMPA configuration becomes suitable for integration with an MMIC.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1738-1745
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• 2015

Radiation characteristics of a probe-fed rectangular microstrip patch antenna printed on a finite grounded high permittivity substrate are investigated systematically for various square grounded dielectric substrate sizes with several thicknesses and dielectric constants by experiment and full wave simulation. The effect of the substrate size on the radiation characteristics of a rectangular patch antenna is mainly determined by the effective dielectric constant of surface waves on a grounded dielectric substrate. As the effective dielectric constant of surface waves increases, the substrate sizes for the maximum broadside gain and the required onset for a large magnitude of squint angle decrease, while the variations of the broadside gain, the front-to-back ratio, and the magnitude of squint angle versus the substrate size increase due to the increase of the power of the surface wave.

• 대한전자공학회논문지TC
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• 제44권11호
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• pp.33-41
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• 2007

기판의 크기가 마이크로스트립 패치 안테나의 방사특성에 미치는 영향에 대하여 알아보았다. 기판의 폭을 고정시키고 길이를 변화시킬 때 방사패턴 특성이 크게 변화하나 기판 길이를 고정시키고 폭을 변화시킬 때는 방사패턴 특성이 거의 변화하지 않음을 볼 수 있었다. 기판 크기에 따른 방사패턴 특성의 변화는 기판 두께가 두꺼울 때가 작을 때보다 더 큼을 볼 수 있었다.

• 대한전자공학회논문지TC
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• 제46권2호
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• pp.114-125
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• 2009

정사각형 기판의 크기가 패치 안테나의 방사 특성에 미치는 영향에 대하여 연구하였다. 기판의 크기가 공진 주파수와 대역폭에 미치는 영향은 매우 작지만 방사 패턴에 미치는 영향은 매우 큼을 볼 수 있었다. 전방방사 이득과 이득이 최대가 되는 각도는 기판의 크기에 따라 거의 주기적으로 변화함을 볼 수 있었다. 전방방사 이득이 최대가 되는 변의 길이와 최소가 되는 변의 길이는 기판의 전기적 두께가 커질수록 작아짐을 볼 수 있었다. 기판의 전기적 두께가 클수록 기판 크기에 따른 전방방사 이득 변화 폭이 큼을 볼 수 있었다. 기판 크기에 따른 방사 패턴의 변화도 기판의 전기적 두께와 매우 밀접한 관계를 가짐을 볼 수 있었다.

• 대한전자공학회논문지TC
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• 제46권6호
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• pp.118-127
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• 2009

정사각형 기판의 크기가 패치 안테나의 방사 특성에 미치는 영향을 연구하기 위하여 마이크로스트립 패치 안테나를 제작하고 측정한 결과를 전산모의한 결과와 비교하였다. 전산모의한 방사 특성 결과와 측정한 방사 특성 결과가 잘 일치함을 볼 수 있었다. 기판의 크기가 패치 안테나의 공진 주파수와 대역폭에 미치는 영향은 작으나 방사패턴에 미치는 영향은 매우 큼을 볼 수 있었다. 기판 두께가 증가할수록 표면파의 발생이 증가하여 기판 크기에 따른 전방 방사 이득 변화 폭, 최대 방사가 일어나는 각도의 변화 폭과 방사패턴의 변화가 크게 발생한다. 기판 두께에 관계없이 기판 크기가 $0.8\;{\lambda}_0$ 일 때 전방방사 이득이 크고 전방방사와 후방방사 이득의 차이도 매우 크다.

• E2M - 전기 전자와 첨단 소재
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• 제9권2호
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• pp.196-203
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• 1996

The highly c-axis oriented zinc oxide thin films were deposited on Sapphire(0001) substrates by reactive RF magnetron sputtering. The characteristics of zinc oxide thin films on RF power, substrate-target distance, and substrate temperature were investigated by XRD, SEM and EDX analyses. The physical characteristics of zinc oxide thin films changed with various deposition conditions. The higher substrate temperatures were, The better crystallinity of zinc oxide thin films. The highly c-axis oriented zinc oxide thin films were obtained at sputter pressure 5mTorr, rf power 200W, substrate temperature 350.deg. C, substrate-target distance 5.5cm. In these conditions, the resistivity of zinc oxide thin films deposited on pt/sapphire was 12.196*10$^{9}$ [.ohm.cm].

• Transactions on Electrical and Electronic Materials
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• 제17권4호
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• pp.217-221
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• 2016

In this work, open and short stubs that were fabricated on the silicon substrate and for which the periodically arrayed grounded-strip structure (PAGS) was employed were studied along with their basic RF characteristics for an applicability regarding the RF-matching components. The PAGS-employing open and short stubs showed losses that are much lower than that of the conventional stub on the silicon substrate. Concretely, the Q values of the open and short stubs are 9 and 10.2, respectively, while the Q value of the conventional open stub is 2.5. With the use of the PAGS-employing open and short stubs, a highly miniaturized harmonic-rejection filter was also fabricated on the silicon substrate. The filter exhibited a comparatively sound harmonic-suppression characteristic at n × 13 GHz, and its size is 0.1 mm², which is only 7% of the size of the conventional filter on the silicon substrate.

• E2M - 전기 전자와 첨단 소재
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• 제8권1호
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• pp.6-12
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• 1995

High Tc superconducting YBa$_{2}$Cu$_{3}$$O_{7-x}$ thin films were prepared on various substrates by off-axis rf magnetron sputtering method to examine the substrate effects on the film structure and its R-T characteristics. The SEM analysis showed that the surface morphology of the grown YBa$_{2}$Cu$_{3}$O.sub 7-x/, film has different characteristic structure with different substrate used. The film on (100) SrTiO$_{3}$ substrate has critical current density of 3*10$^{5}$ A/cm$^{2}$ at 77K under zero magnetic field. The X-ray diffraction measurements revealed that the films on (100) SrTiO$_{3}$ substrate have mixed a-axis and c-axis normal to the substrate surface and the films on (100) MgO and ZrO$_{2}$/sapphire substrates have c-axis normal orientation to the substrate surface. However, YBa$_{2}$Cu$_{3}$$O_{7-x}$ films on (100) sapphire substrates showed no preferential orientation.ion.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.387-392
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• 2018

Static characteristics of SiC (silicon carbide) lateral p-i-n diodes implemented on semi-insulating substrate without an epitaxial layer are inVestigated. On-axis SiC HPSI (high purity semi-insulating) and VDSI (Vanadium doped semi-insulating) substrates are used to fabricate the lateral p-i-n diode. The space between anode and cathode ($L_{AC}$) is Varied from 5 to $20{\mu}m$ to inVestigate the effect of intrinsic-region length on static characteristics. Maximum breakdown Voltages of HPSI and VDSI are 1117 and 841 V at $L_{AC}=20{\mu}m$, respectiVely. Due to the doped Vanadium ions in VDSI substrate, diffusion length of carriers in the VDSI substrate is less than that of the HPSI substrate. A forward Voltage drop of the diode implemented on VDSI substrate is 12 V at the forward current of $1{\mu}A$, which is higher than 2.5 V of the diode implemented on HPSI substrate.

• 반도체디스플레이기술학회지
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• 제19권3호
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• pp.100-105
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• 2020

Recently, as display and semiconductor devices have been miniaturized and highly integrated, there is a demand for optimization of the structural characteristics of the thin film accordingly. The sputtering device has the advantage of stably obtaining a desired thin film depending on the material selected for the target. However, due to the structural characteristics of the sputtering equipment, the structural characteristics of the film may be different depending on the incidence angle of the sputtering target material to the substrate. In this study, the characteristics of the thin film material according to the scattering angle of the target material and the incidence position of the substrate were studied to find the optimization design rule of the sputtering equipment. To this end, a Si thin film of 1 ㎛ or less was deposited on the Si(100) substrate, and then the microstructure, reflectance, surface roughness, and thin film crystallinity of the thin film formed for each substrate location were investigated. As a result of the study, it was found that as the sputter scattering angle increased and the substrate incident angle decreased, the gap energy along with the surface structure of the thin film increased from 1.47 eV to 1.63 eV, gradually changing to a non-conductive tendency.