• Progress in Superconductivity
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• v.14 no.2
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• pp.102-105
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• 2012

We are developing meander-shaped metallic magnetic calorimeters using micro-fabrication methods. A planar Nb coil in a meander shape was fabricated on a Si substrate. The coil was designed to have a persistent current using a metal heater evaporated on a part of the coil. A paramagnetic sensor, $5{\mu}m$ thick Au:Er foil, was glued on top of the meander structure with epoxy. The magnetization and heat capacity were measured at different temperatures, and applied field currents matched well with expected values. The detector showed an energy resolution of 4 keV FWHM for the 5.5 MeV alpha particles.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.159-162
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• 2002

The eleventh-order coupled line lowpass filter(LPF) was designed to suppress harmonics and spurious signals. The microstrip type LPF was fabricated using a high-$T_{c}$ superconductor(HTS) $YBa_{2}$$Cu_{3}$$O_{7-x}$(YBCO) thin film with the $CeO_{2}$ buffer layer which was deposited on the sapphire ($Al_{2}O_{3}$) substrate of 30 x 30 $mm^{2}$. The coupled-line type LPF was designed for 1.2 GHz of cutoff frequency with 0.01 dB of ripple level at passband. The fabricated HTS LPF shows excellent attenuation characteristics in stopband of 1.2~9.5GHz (7-attenuation poles in the stopband), and shows low insertion loss (0.2 dB) and return loss (17.1 dB) in the pass- band. These measured results match well with those obtained by the EM simulation. This clearly demonstrates that the HTS LPF can suppress harmonics and spurious signals effectively.

• Journal of electromagnetic engineering and science
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• v.10 no.3
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• pp.171-174
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• 2010

In the paper, a printed dual-dipole array antenna is presented. A 4-way planar SIW power divider is adopted for feeding the array antenna. The dual-dipole is adopted as radiation elements which greatly improves the impedance band. The measured bandwidth larger than 31 % for VSWR$\leq$1.5 operating near 14 GHz is achieved and in agreement with the simulated results. The radiation E-plane and H-plane radiation pattern is presented in the paper. The radiation gain is also presented in the paper.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.161-166
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• 2007

In this paper, two 4$\times$4 rectangular patch array antennas operating at 20 GHz are implemented for the satellite communication. The sixteen patch antennas and microstrip feeding line are printed on a single-layered substrate. The design goal is to achieve high directivity and gain by optimizing design parameters through permutations in element spacing. The spacing between the array elements is chosen to be 0.736$\lambda$. Numerical simulation results indicate that the HPBW(Half-Power Beam Width) of the 4$\times$4 patch array antenna is 18.78 degrees in the E-plane and 18.48 degrees in the H-plane with a gain of 17.18 dBi. Numerical simulations of a 4$\times$4 recessed patch array antenna yield a HPBW of 18.71 degrees in the E-plane and 17.82 degrees in the H-plane with a gain of 19.43 dBi.

• Journal of Information Display
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• v.1 no.1
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• pp.20-24
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• 2000

We propose on a novel vertical configuration (VC) for a helix-deformed ferroelectric liquid crystal (HDFLC) display that has fast response, high contrast, analog gray scale capability, and wide-viewing characteristics. In contrast to a conventional HDFLC in a planar geometry, smectic layers arrange themselves parallel to the substrates, and thus, extremely uniform alignment of molecules in large area is naturally achieved in our new configuration without additional processes such as the rubbing and/or electric field treatment. Moreover, with a proper design of electrode patterns on the same substrate, multidomain switching is easily realized without employing any complex process of alignment. Our new VC-HDFLC is expected to provide a viable technology to produce a next-generation large area LCD suitable for processing the dynamic image at a video-rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.1
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• pp.143-149
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• 1993

An approach is presented for efficient numerical integration of the Sormnerfeld type integrals pertinent to the microstrip surface Green's function arising in the problem of an electric current point source on an infinite planar grounded dielectric substrate. This approach, valid for both lossless and lossy dielectric substrates, is based on the deformation of the integration contour via a coordinate transformation and Cauchy's residue theory, and identifies clearly the effects of surface waves. I ts useful application is in a rigorous moment method analysis of micros trip antenna arrays and microstrip guided wave structures. The efficiency and the usefulness of the present approach are emphasized through some numerical calculations of the impedance matrix elements with associated CPU times.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1454-1456
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• 2001

신장병 진단에 중요한 요소의 농도를 측정하기 위한 요소 센서를 반도체 위에 개발이 연구의 목적이다. 센서의 감도 측정은 선형 전위 주사법(Linear sweep voltammtry)을 이용하였다. 선형 전위 주사법은 가역적이든 비가역적이든 관계없이 cottrell 식에 의한 전류와 농도의 직선관계로부터 감도를 측정할 수 있는 장점이 있고 또한 저 농도에서 민감하게 반응한다. 따라서 기존 전위차 측정형 바이오 센서(Potentiometric biosensor)에서 규명할 수 없는 감도 문제를 선형 전위 주사법으로 규명하고자 하였다. 센서전극은 p-type 실리콘 웨이퍼 위에 전극을 제작했다. 그 위에 cyclic voltammetry 법을 사용하여 전도성 고분자를 전기 중합 하였고, 그위에 다시 chronoamperometry법을 사용하여 우레아제를 고정화 하여 작업전극으로 제작하였다. 센서의 감도는 phosphate buffer 용액(pH7.4)속에서 온도 35$^{\circ}C$를 유지하며 측정하였다.

• Journal of the Korean Ceramic Society
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• v.37 no.6
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• pp.524-529
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• 2000

Silica slab wavegudie was fabricated on Si substrates by FHD for planar optical passive devices. The slab waveguide consists of lower clad and core layers, where core layer index is controlled by GeO2 addition. Doping of GeO2 in silica is difficult because of the low deposition density due to nonspherical particle generation in FHD process. Silica core particles deposited at various conditions such as flame temperature and substrate scanning were analyzed by SEM and TEM. As the flame temperature increased, the surface roughness of the core layer was decreased up to 3.6 nm after consolidation. Index difference and thickness of core of slab waveguide were 0.3%, 8$\mu\textrm{m}$ respectively. Measured optical loss at TE mode was <0.04 dB/cm at 1.3$\mu\textrm{m}$ and <0.06 dB/cm at 1.55$\mu\textrm{m}$.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.1
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• pp.133-139
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• 1987

A phase-locked Channel-Substrate-Planar(CSP) laser arrays is described. Arrays of emitters with weak coupling are operated in a set of discrete modes determined by the number and spacing of the emitters. The interactions between emitters lead to a splitting of the wave-length and gain which are calculated from the coupling strength. Phase-locked arrays has exhibited to CW output-power as high as 80 m W and the highest order mode will have preferred oscillation. A strong hole burning is occurred at p=30m W. The most stable lasing mode is occurred at element spacing S=3.5\ulcornerm and there is no coupling at S>7 \ulcornerm.

• Proceedings of the Optical Society of Korea Conference
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• 1991.06a
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• pp.190-193
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• 1991

The monolithically integrated receiver OEIC using InGaAs/InP PIN PD, junction FET's and bias resistor has been fabricated on semi-insulating InP substrate. The fabrication process is highly compatible between PD and self-aligned JFET, and reduction in gate length is achieved using an anisotropic selective etching and a non-planar OMVPE process. The PIN photodetector with a 80 ${\mu}{\textrm}{m}$ diameter exhibits current of less than 5 nA and a capacitance of about 0.35 pF at -5 V bias voltage. An extrinsic transconductance and a gate-source capacitance of the JFET with 4 ${\mu}{\textrm}{m}$ gate length (gate width = 150 ${\mu}{\textrm}{m}$) are typically 45 mS/mm and 0.67 pF at 0 V, respectively. A voltage gain of the pre-amplifier is 5.5.