• The Magazine of the IEIE
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• v.38 no.9
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• pp.17-22
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• 2011

• KIPE Magazine
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• v.24 no.3
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• pp.30-35
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• 2019

• Proceedings of the Korean Magnestics Society Conference
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• 2004.06a
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• pp.234-235
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• 2004

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.6
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• pp.578-583
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• 2016

In this paper, we propose a multi-mode wireless power transfer (WPT) system with a dual loop structure. The proposed multi-mode WPT system consist of outer loop module which can operate at two different frequency bands including 6.78 MHz magnetic resonance WPT mode and 13.56 MHz near field communication (NFC) mode and inner loop module connected with outer loop which can operate at two different frequency bands including WPC mode and PMA mode based on inductive coupling standards. In order to be able to embed this system into smartphone battery back cover, the electrical designs are optimized and then the size was fixed $45{\times}90{\times}0.35mm3$ (including ferrite sheet) which is the same commercial smartphone. The proposed multi-mode WPT module can cover WPC and PMA mode based on inductive coupling. Moreover, it has more than 20 dB return loss characteristics at two different frequency bands including 6.78 MHz and 13.56 MHz, and shows more than 70 % transfer efficiency between resonant coils at 6.78 MHz in magnetic resonant charging environment.

• Journal of Sensor Science and Technology
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• v.8 no.5
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• pp.407-413
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• 1999

The resonant frequency of dielectric rod resonator can be calculated very accurately by means of the concept of electric and magnetic walls from the symmetry. But in a real situation, when the supporter is placed in the cavity, asymmetry appears due to the supporter and its dielectric constant. Then we need research into the resonance characteristic of asymmetric dielectric resonator. In this paper, for the dielectric rod resonator which is placed in the asymmetric position in the conducting cavity, the equation for resonance characteristic was derived and the resonant frequency was calculated with the eigenfunction expansion method. We found that the calculated resonant frequency is very accurate when it was compared with the experimental result and that asymmetry affects the resonant frequency more in TM mode than in TE or in hybrid mode.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.4
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• pp.387-394
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• 2000

The nonlinear modal interaction of an autoparametric system under a broadband random excitation is investigated. The specific system examined is an autoparametric vibration absorber with internal resonance, which is typical of many common structural configurations. By means of Gaussian closure scheme the dynamic moment equations explaining the random responses of the system are reduced to a system of autonomous ordinary differential equations of the first and second moments. In view of equilibrium solutions of this system and their stability we examine the system responses. We could not find the destabilizing effect of damping, which was reported in References (18) and (20). The saturation phenomenon, which is well known in deterministic nonlinear system, did not take place lot this system subject to broadband random excitation.

• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.614-619
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• 2017

In this paper, we optimize the wireless power transmission (WPT) coil, and then compare the EM simulation and measurement using magnetic coupling at 6.78 MHz. As transmission efficiency is affected by various factors such as the shape of the system, the size of the coils, the coil structure is proposed to consist of a helical resonant for transmission and a spiral resonant for reception. The size of the coil and the distance between the coils are determined to minimize the volume problem, and the shape of the coil are confirmed by EM simulation. A WPT system is designed with 860mm diameter top plate and cylindrical structure of column spaced 600mm apart, and the characteristics are simulated and measured. The simulation shows that ${\mid}S_{21}{\mid}$ is -0.53 dB with the efficiency of 88%, and the measurement result is that ${\mid}S_{21}{\mid}$ is -0.71 dB with the efficiency of 85%.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1269-1270
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• 2015

외부에서 발생되는 전자파가 특정 구조물 내에 침투하는 경우, 특히 구조체가 도체로 이루어 졌을 때, 구조체의 크기에 따른 특정 주파수가 공진을 일으켜 내부 PCB(Printed Circuit Board), 회로 등에 악영향을 미친다. 본 논문에서는 개구면이 존재하는 공진기에 전자기파가 입사되는 상황을 모드매칭(MM: Mode Matching)을 이용해서 해석한다. 이때 외부 전자파로 인해 개구면에 생기는 새로운 소스를 표면 등가 이론(Surface equivalence theorem)을 이용하여 등가 자기전류로 모델링하여, 공진기 내 외부의 전자기장을 구한 후 개구면에서 접선성분의 경계조건을 적용시켰다. 본 논문에서 사용된 계산식의 검증을 위해 3차원 유한 요소법(FEM: Finite Element Method)기반의 프로그램인 HFSS를 이용 하였다.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.7-8
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• 2014

본 논문은 다이폴 코일 공진방식(DCRS, Dipole Coil Resonant System)을 사용한 원격 무선전력전송 개발 사례를 소개한다. 제안된 다이폴 코일 공진방식은 기존의 자기결합 공진방식(CMRS, Coupled Magnetic Resonance System)에 비하여 송신, 수신코일로만 이루어진 간단한 코일 구조와 작은 부피를 가지며, 공진도 Q를 100이하로 설계하여 주변 환경 변화에 강인한 전력전달 특성을 가진다. 본 논문에서는 원전 중대사고 시 격납건물 필수계측기용 소형 비상전원으로 개발된 10W급 7m 원격 무선전력전송 장치의 구성 및 설계과정을 제시한다.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.60-61
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• 2010

본 논문에서는 휴머노이드 로봇 등에 적용하기 위해, 평판형 급전코일과 집전코일의 접촉 유무에 따라 공진주파수가 변화하는 접촉식 무선충전 시스템을 제안하였다. 다양한 급집전코일에 대해 코일의 형상과 위치별 급집전효율 및 EMF(ElectroMagnetic Field)의 영향을 연구했다. 평판형 집전코일은 어레이 형태로 바닥에 설치되는데, 입력전원에 대해 각각 병렬로 연결되어 있어서 집전코일이 접촉하지 않는 경우에는 공진주파수가 입력전원의 주파수를 크게 벗어나서 자동으로 전원공급이 최소화된다. 집전코일이 급전코일 어레이 위에 위치하는 경우에는, 급전코일의 공진주파수가 입력전원의 주파수와 일치하게 되어 전력이 공급되게 된다. 따라서 집전코일이 덮고 있는 부분만 급전코일 어레이에 전력이 공급되므로, 급집전 효율이 높고 인체에 대한 자기장 노출이 작아져서, 경제적이고 안전한 무선충전 시스템을 구성할 수 있다.