• Journal of electromagnetic engineering and science
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• 제18권1호
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• pp.46-51
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• 2018

In this paper, a planar printed hybrid short/open-ended slot antenna with capacitive coupling feed strips is proposed for hepta-band mobile applications. The proposed antenna is comprised of a slotted ground plane on the top plane and two capacitive coupling feed strips with a chip inductor on the bottom plane. At the low frequency band, the short-ended long slot fed by strip 1 generates its half-wavelength resonance mode, whereas the T-shaped open ended slot fed by strip 2 generates its quarter-wavelength resonance mode for the high frequency band. The antenna provides a wide bandwidth covering GSM850/GSM900/DCS/PCS/UMTS/LTE2300/LTE2500 operation bands. Moreover, the antenna occupies a small volume of $15mm{\times}50mm{\times}1mm$. The operating principle of the proposed antenna and the simulation/measurement results are presented and discussed.

• 한국통신학회논문지
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• 제33권9A호
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• pp.934-940
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• 2008

본 논문에서는 GPS, DCS, PCS, UMTS, Wibro, Bluetooth, S-DMB대역에서 동작 가능한 안테나를 설계하고 제작하였다. 최대한 적은 부피의 안테나로 광대역 특성을 얻기 위해 모노폴 안테나를 기반으로 CPWG(Coplanar Waveguide-fed with Ground) 급전 구조를 사용하였다. 방사패치의 길이와 방사패치와 접지면 간의 간격을 조정하며 시뮬레이션 하였으며, 최적화된 파라미터를 가지고 제작하였다. 제작된 안테나는 VSWR<2에서 1.430Hz$\sim$2.9GHz(67.89%)의 대역폭과 $1.3{\sim}3.7dBi$의 이득 및 전방향성(Omni-directional) 방사패턴을 얻었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.277-277
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• 2012

PCDTBT (Poly[N-9''-hepta-decanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)]) is an attractive material as a semiconducting polymer for organic thin film transistor (OTFT) and organic solar cell (OSC). High power conversion efficiency (~6%) under simulated AM 1.5G solar illumination of bulk-heterojunction solar cell with PCDTBT and [6,6]-phenyl C60 butyric acid methyl ester (PC61BM) blend was reported. In OSC, it is known that the band alignment at the interface between donor and acceptor is critical. Therefore, we studied the interfacial electronic structures of PCDTBT and PC61BM. The polymers are deposited by electro-spray on gold and In-situ x-ray and ultraviolet photoelectron spectroscopy measurements revealed the interfacial electronic structures. We obtained the energy level alignment between two materials and the different interface formation was observed with different deposition order.

• 한국전기전자재료학회논문지
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• 제30권10호
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• pp.625-630
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• 2017

ZnS was chemically deposited as a buffer layer alternative to CdS, for use as a Cd-free buffer layer in $Cu(In_{1-x}Ga_x)Se_2$ (CIGS) solar cells. The deposition of a thin film of ZnS was carried out by chemical bath deposition, following which the structural and optical properties of the ZnS layer were studied. For the experiments, zinc sulfate hepta-hydrate ($ZnSO_4{\cdot}7H_2O$), thiourea ($SC(NH_2)_2$), and ammonia ($NH_4OH$) were used as the reacting agents. The mole concentrations of $ZnSO_4$ and $SC(NH_2)_2$ were fixed at 0.03 M and 0.8 M, respectively, while that of ammonia, which acts as a complexing agent, was varied from 0.3 M to 3.5 M. By varying the mole concentration of ammonia, optimal values for parameters like optical transmission, deposition rate, and surface morphology were determined. For the fixed mole concentrations of $0.03M\;ZnSO_4{\cdot}7H_2O$ and $0.8M\;SC(NH_2)_2$, it was established that 3.0 M of ammonia could provide optimal values of the deposition rate (5.5 nm/min), average optical transmittance (81%), and energy band gap (3.81 eV), rendering the chemically deposited ZnS suitable for use as a Cd-free buffer layer in CIGS solar cells.