• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1420-1421
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• 2008

In this paper, a dual band microstrip filter is designed for RFID Application. Both magnetic and electric coupling structures are implemented to provide high performance passband response. The measured results demonstrate that reflection factor is 20dB and 15dB at 912MHz and 2450MHz. The measured loss is 2.6dB and 2.8dB at 912MHz and 2450MHz, respectively.

• Coupled systems mechanics
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• 제6권4호
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• pp.465-485
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• 2017

In this paper, free vibration and static response of magneto-electro-elastic (MEE) beams has been investigated. To this end, a 3D finite element formulation has been derived by minimization the total potential energy and linear constitutive equation. The coupling between elastic, electric and magnetic fields can have a significant influence on the stiffness and in turn on the static behaviour of MEE beam. Further, different Barium Titanate ($BaTiO_3$) and Cobalt Ferric oxide ($CoFe_2O_4$) volume fractions results in indifferent coupled response. Therefore, through the numerical examples the influence of volume fractions and boundary conditions on the natural frequencies of MEE beam is illustrated. The study is extended to evaluate the static response of MEE beam under various forms of mechanical loading. It is seen from the numerical evaluation that the volume fractions, loading and boundary conditions have a significant effect on the structural behaviour of MEE structures. The observations made here may serve as benchmark solutions in the optimum design of MEE structures.

• 한국진공학회지
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• 제5권1호
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• pp.85-92
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• 1996

The external electricla characteristics of helicon wave plasmas were measured over a wide range of RF power and magnetic filed. External parameters. such as antenna voltage , current, phase shift, and interanl parameter, electron density were measured at 7MHz, 1mTorr Ar discharge . The equivalent discharge resistance and reactance, and the power transfer efficiency were calculated through these measurements. There are a helicon mode which produces high density plasma by helicon wave and a lowmode which produces low density plasma by capaictive electric field. In case of the helicon mode, the anternna voltage and current were lower than those of the low-mode. The phase difference between voltage and current decreased suddenly at the transition point from the low-mode to the helicon mode. Equivalent resistance and power efficiency increased and reactance decreased suddenly at the transition point. These results mean that the power transperred to plasma and the nutual coupling between the antenna and plasma increase as the mode changes from the low-mode to the helicon mode.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 전력전자학술대회 논문집
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• pp.429-430
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• 2015

본 논문에서는 권선 사이의 자계결합도 변동을 고려한 자기 공진 방식의 전기차 충전용 무선전력전송회로의 설계기법을 제시한다. 자기공진 방식의 전기차 충전용 무선전력전송회로는 LLC 공진형 컨버터와 동작원리가 유사하지만 설계측면에서는 회로의 동작주파수가 표준규격에 의해서 일정범위로 제한되고 1차측과 2차측 권선의 정렬상태에 따라서 자계결합도가 변동할 수 있다는 점에서 LLC 컨버터와는 차이가 있다. 본 논문에서는 동작주파수의 제한범위 및 자계결합도의 변동을 고려한 무선전력전송회로의 설계기법을 제시하는 한편, 시뮬레이션을 통하여 설계를 검증한다.

• Current Optics and Photonics
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• 제5권3호
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• pp.329-335
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• 2021

The problem of polarized light scattering by a cylinder on or close to a planar substrate is analytically solved. The light is assumed to be normally incident to the axis of the cylinder. Transverse magnetic (TM) and transverse electric (TE) polarizations are treated separately. The solution for each polarization is composed of a coupled set of linear equations which couples the scattering characteristics of the cylinder and the planar substrate. The coupling comes from the scattering by the planar substrate and by the cylinder. The solution of the coupled set of equations obtained by iterative substitution consists of infinite series, where each term represents the contribution of single and multiple scatterings of all orders.

• Journal of Power Electronics
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• 제16권6호
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• pp.2359-2367
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• 2016

Inductive power transfer (IPT) systems have become increasingly popular in recharging electric vehicle (EV) batteries. This paper presents an investigation of a series parallel/series (SP/S) resonant compensation network based IPT system for EVs with further optimized circular pads (CPs). After the further optimization, the magnetic coupling coefficient and power transfer capacity of the CPs are significantly improved. In this system, based on a series compensation network on the secondary side, the constant output voltage, utilizing a simple yet effective control method (fixed-frequency control), is realized for the receiving terminal at a settled relative position under different load conditions. In addition, with a SP compensation network on the primary side, zero voltage switching (ZVS) of the inverter is universally achieved. Simulations and experiments have been implemented to validate the favorable applicability of the modified optimization of CPs and the proposed SP/S IPT system.

• 전력전자학회논문지
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• 제12권2호
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• pp.174-182
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• 2007

신재생에너지 중에서 태양광 에너지가 중요 에너지원으로서 각광받고 있고 적용이 증대되고 있다. 특히, 미래에는 하이브리드 태양광 발전 시스템이 독립 분산 전원 시스템으로 널리 사용될 것으로 예상되고 있다. 본 논문에서는 DC전력을 기계적인 접촉에 의해 전달하는 것보다는 마그네틱 커플링에 의해 비접촉으로 에너지를 전달 할 수 있는 무접점전원장치를 사용한 직류수용가 서비스 태양광발전시스템을 제안하였다. 제안 적용된 무접점 전원장치는 무접점 변압기와 Half-bridge LLC 공진컨버터, 영 전압 스위칭 Boost컨버터로 구성되어 있다.

• 한국재료학회지
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• 제15권10호
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• pp.639-643
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• 2005

Lead-free $[Bi_{0.5}(Na_{1-x}K_x)_{0.5}TiO_3](x=0\~1.0)$ ceramics were prepared using a solid state reaction method and their structural and electrical characteristics were investigated. X-ray investigations indicated that the rhombohedral-tetragonal morphotropic phase boundary(MPB) of the $[Bi_{0.5}(Na_{1-x}K_x)TiO_3$ ceramics exists in the range of $x=0.16\~0.20$. The optimum values of piezoelectric constant$(d_{33})$, dielectric constant, and electromechanical coupling factor $(k_p)$ were obtained at $x=0.16\~0.20$ of the MPB region.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.317-321
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• 2002

Piezoelectric properties of $(Pb_{1-x}Y_x)[(Ni_{1/3}Nb_{2/3})_{0.15}(Zr_{1/2}Ti_{1/2)})_{0.85}]O_{3}$ (x=0~0.05) ceramics were investigated, The stoichiometric PNN-PZT ceramics required the sintering temperature above $1100^{\circ}C$, but the addition of $Y_{2}O_{3}$ in the PNN-PZT ceramic lowered the sintering temperature down to $1000^{\circ}C$. In case of x=0.005, the electro-mechanical coupling $factor(K_p)$, the piezoelectric $constant(d_{33})$, and the maximum strain ratio of PNN-PZT ceramics sintered at $1000^{\circ}C$ were 53.1%, 395pC/N, and $2200{\times}10^{-6}$ respectively, A 30-layer piezoelectric actuator$(10{\times}10{\times}1.7mm)$ fabricated with the above material showed the maximum strain of $2.09{\mu}m$ under 100V DC bias.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.334-337
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• 2002

In this study, the microstructure, dielectric and piezoelectric properties of $0.15Pb(Ni_{1/3}Nb_{2/3})O_3-0.85(PbZr_{0.5}Ti_{0.5})O_3$(0.15PNN-0.85PZT) ceramics having compositions near the morphotropic phase boundary(MPB) was investigated with respect to the variation of $Y_2O_3$ and $Ga_2O_3$ addition amount. The dielectric properties increased and piezoelectric properties decreased with increasing the amount of $Ga_2O_3$. The solubility limit of $Y_2O_3$ is 0.5mol% in this system. The electro-mechanical coupling factor$(K_p)$ and dielectric constant(${\varepsilon}_r$) were 58.6% and 1755 when the amount of $Y_2O_3$ are 0.5mol%.