• Journal of the Korea Society of Computer and Information
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• v.3 no.3
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• pp.107-112
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• 1998

In this paper, filter designed and produced to use hi-Z low-Z filter which is easy to produce microstrip line and uses space less than used stub filter. This filter has very short electrical length of lines, that is Bl＜$\pi$/4, lowpass prototype series inductor replaced high impedance line section and shunt capacitance replaced low impedance line section. Replaced each section designed microstrip lines and effective permittivity of the given microstrip calculated and each section width and length calculated dna filter used design. Designed filter compared the theory value of touchstone with the experiment value of real produced filter and an analyzed response charictristic.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.2
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• pp.155-165
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• 1996

Growth of $LiNbO_3$ single crystal by Czochralski method was carried out to study the piezoelectric effects. Piezoelectric coefficients and elastic compliances of the $LiNbO_3$ single crystal were determined by the resonance method of length-extentional mode of bar resonator from the room temperature up to $100^{\circ}C$. Two dielectric constants of $LiNbO_3$ were also determined by measuring the capacitance of the plate specimen. Measured constants were piezoelectric coefficients $d_{15},d_{22},d_{31},d_{33}$ elastic compliances $s^E_{11},s^E_{33},2s^E_{13}+2s^E_{44},s^E_{14}$ and dielectric constants $K^T_{11},K^T_{33}$. As temperature increased, elastic compliances changed very slowly while piezoelectric coeffiecients and dielectric constant $K^T_{33}$ changed very rapidly. Electromechanical coupling constant of zyw ($45^{\circ}C$)-bar was as high as 0.51 in room temperature and nearly constant up to $1000^{\circ}C$. The increase of piezoelectric coefficients was mainly due to the increase of dielectric permittivity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.34-38
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• 2000

Recently, the ceramics of high permittivity are applied to DRAM and FRAM. In this study, (Ba, Sr)$TiO_3$ (BST) ceramics thin films were prepared by Sol-Gel method. BST solution was made and spin-coated on Pt/$SiO_2$/Si substrate at 4000 [rpm] for 10 seconds. Coated specimens were dried at $150[^{\circ}C]$ for 5 minutes. Coating process was repeated 3 times and then sintered at $750[^{\circ}C]$ for 30 minutes. Each specimen was analyzed structure and electrical characteristics by Fractal Process. Thickness of BST ceramics thin films are about $2000{\AA}$. Dielectric constant and loss of thin films was little decreased at 1[KHz] - 1[MHz]. Dielectric constant and loss to frequency were 250 and 0.02 in BST3. The property of leakage current as the realation between the current and the voltage was that change of the leakage current was stable when the applied voltage was 0~3[V].

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.271-271
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• 2010

$BaTiO_3$(BT) has high permittivity so that has been applied to dielectric and insulator materials in 3D system-level package integration. In order to achieve excellent performance of device, the BT layer should be highly dense. In this study, BT thick films were prepared by the inkjet printing method. And these films were cured at $280^{\circ}C$ after infiltration of polymer resin. As a result, we have successfully fabricated not only the inkjet-printed hybrid BT film but also metal-insulator-metal(MIM) capacitor without sintering process. Changes in the dielectric constant of BT hybrid film with particle size and packing density were investigated. The dielectric constant was increased with increasing packing density and particle size. Further, the BT hybrid film using two different size particles had even higher packing density and dielectric constant.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.31-31
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• 2008

고주파 잡음 발생과 고집적화 문제 해결을 위해 고용량 디커플링 캐패시터를 기판에 내장하는 연구가 활발히 진행되고 있다. 본 연구에서는 초고주파 환경에서 고용량 기판 내장형 디커플링 캐패시터로의 응용을 위해 $BaTiO_3$박막을 에어로졸 데포지션 법을 이용하여 12~0.2 ${\mu}m$의 두께로 제조하였고 그 유전특성을 조사하였다. 그결과, 1 MHz에서 permittivity가 70, loss tangent은 3% 이하였으며, capacitance density는 $1{\mu}m$의 두께에서 59 nF/$cm^2$이었다. 하지만, 박막의 두께가 $1{\mu}m$ 이하에서는 XRD를 통해 결정성이 확인 되었음에도 큰 누설전류로 인해 유전특성을 확인할 수 없었다. 이 누설전류의 발생 원인을 조사하기 위해 $BaTiO_3$박막의 표면의 미세구조를 SEM으로 관찰한 결과 여러 결함들이 확인되었으며, 또한 전극 직경의 크기를 1.5 mm에서 0.33 mm로 작게 변화시킴으로서 그 유전특성을 조사하여 박막의 불균일성과 박막화의 가능성을 확인하였다.

• Journal of Environmental Science International
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• v.14 no.10
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• pp.919-928
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• 2005

This study introduces the development of new supercritical water oxidation(SCW)(multiple step oxidation) to destruct recalcitrant organic substances totally and safely by using sodium nitrate as an oxidant. This method has solved the problems of conventional SCW, such as precipitation of salt due to lowered permittivity, pressure increase following rapid rise of reaction temperature, and corrosion of reactor due to the generation of strong acid. Destruction condition and rate in the supercritical water were examined using Polyvinyl Chloride(PVC) and ion exchange resins as organic substances. The experiment was carried out at $450^{\circ}C$ for 30min, which is relatively lower than the temperature for supercritical water oxidation $(600-650^{\circ}C)$. The decomposition rates of various incombustible organic substances were very high [PVC$(87.5\%)$, Anion exchange resin$(98.6\%)$, Cationexchange resin$(98.0\%)$]. It was observed that hetero atoms existed in organic compounds and chlorine was neutralized by sodium (salt formation). However, relatively large amount of sodium nitrate (4 equivalent) was required to raise the decomposition ratio. For complete oxidation of PCB was intended, the amount of oxidizer was an important parameter.

• Investigative Magnetic Resonance Imaging
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• v.20 no.1
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• pp.36-43
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• 2016

Visualization of the tissue loss tangent property can provide distinct contrast and offer new information related to tissue electrical properties. A method for non-invasive imaging of the electrical loss tangent of tissue using magnetic resonance imaging (MRI) was demonstrated, and the effect of loss tangent was observed through simulations assuming a hyperthermia procedure. For measurement of tissue loss tangent, radiofrequency field maps ($B_1{^+}$ complex map) were acquired using a double-angle actual flip angle imaging MRI sequence. The conductivity and permittivity were estimated from the complex valued $B_1{^+}$ map using Helmholtz equations. Phantom and ex-vivo experiments were then performed. Electromagnetic simulations of hyperthermia were carried out for observation of temperature elevation with respect to loss tangent. Non-invasive imaging of tissue loss tangent via complex valued $B_1{^+}$ mapping using MRI was successfully conducted. Simulation results indicated that loss tangent is a dominant factor in temperature elevation in the high frequency range during hyperthermia. Knowledge of the tissue loss tangent value can be a useful marker for thermotherapy applications.

• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.3
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• pp.136-147
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• 2009

In this paper we analyze the influence of source/drain (S/D) extension region design for minimizing short channel effects (SCEs) in 25 nm gate length single and double gate Silicon-on-Insulator (SOI) and Germanium-on-Insulator (GOI) MOSFETs. A design methodology, by evaluatingm the ratio of the effective channel length to the natural length for the different devices (single or double gate FETs) and technology (SOI or GOI), is proposed to minimize short channel effects (SCEs). The optimization of non-overlapped gate-source/drain i.e. underlap channel architecture is extremely useful to limit the degradation in SCEs caused by the high permittivity channel materials like Germanium as compared to that exhibited in Silicon based devices. Subthreshold slope and Drain Induced Barrier Lowering results show that steeper S/D gradients along with wider spacer regions are needed to suppress SCEs in GOI single/double gate devices as compared to Silicon based MOSFETs. A design criterion is developed to evaluate the minimum spacer width associated with underlap channel design to limit SCEs in SOI/GOI MOSFETs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.11a
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• pp.59-62
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• 1992

In this study, $TiO_2$ thin films are fabricated by Sol-Gel method and dielectric, electric and humidity sensing properties have been investigated. The structure of Sol can be changed by controlling for hydrolysis reaction condition. The uniformity of the surface on $TiO_2$ thin films is confirmed by SEM. The permittivity of $TiO_2$ thin films increases according to heat treatment temperature, whereas the conductivity of $TiO_2$ thin films decreases according to heat treatment temperature, As the results of measuring humidity sensing properties of $TiO_2$ thin films fabricated as humidity sensor, it is confirmed to have good humidity sensing properties in high humidity and low frequency.

• Journal of the Korea Computer Industry Society
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• v.5 no.2
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• pp.331-336
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• 2004

In this paper, an antenna for telematics is proposed. It operates at GPS/GSM frequency-bands and it can be installed inside of a vehicle. There is a great difference between the proposed antenna and commonly used antennas. It needs not to use a dielectric with a high permittivity since it is formed on a sheet of FR4 with only 1mm thickness. Thus, it is possible to cut costs and make process of manufacture simple. Planar inverted-F antenna(PIFA) for GSM and microstrip antenna(MSA) for GPS is designed and PIFA-MSA antenna is proposed. The height is lower than that of commonly used antennas. And polarization of the PIFA and MSA is arranged perpendicularly for isolation improvement of each port, thus isolation of these two antennas is improved. Also, it is sufficient for the all specifications.