• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.3
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• pp.366-375
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• 2008

Generally a return current plane(RCP) of high speed digital and analog part is partitioned. This is achieved in order to decrease the noise interference between subsystem in PCBs(Printed Circuit Boards). However, when the connected signal line exists between each sub system, this partition will cause unwanted effects. In a circuital point of view, RCP partition has a bad influence upon signal integrity. In a EMI(Electromagnetic Interference) point of view, the partition of the return current plane becomes a primary factor to increase the radiated emission. Component bridge(CB) is usecl for the way of maintaining signal integrity, still specific user's guide doesn't give sufficient principle. In a view point of signal integrity, design principle of multi-CB using method will be analyzed by measurement and simulation. And design principle of noise mitigation will be provided. Generally interval of CB is ${\lambda}/20$ ferrite bead. In this study. When multi-CB connection is applied, design principle of ferrite bead and chip resistor is proved by measurement and simulation. Multi-connected chip resistance$(0{\Omega})$ is proved to be more effective design method in the point of signal integrity.

• Journal of the Korean Magnetics Society
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• v.18 no.1
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• pp.43-47
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• 2008

[ $ZnO-Bi_2O_3-Al_2O_3-B_2O_3-SiO_2$ ] nano-glass has been prepared by sol-gel method. The mean particle size was 60.3 nm with narrow size distribution. The nano-galss has been used as a sintering aid for the densification of the NiZnCu ferrites. The ferrite was sintered with nano-glass sintering aids at $840{\sim}900^{\circ}C$, 2 h and the initial permeability, quality factor, density, and saturation magnetization were also measured. The initial permeability of 0.5 wt% nano-glass added toroidal sample for NiZnCu ferrites sintered at $900^{\circ}C$ was 193.3 at 1 MHz. The initial permeability and saturation magnetization were increased with increasing annealing temperature. As a result, $ZnO-Bi_2O_3-Al_2O_3-B_2O_3-SiO_2$ nano-glass systems were found to be useful as sintering aids for multilayer chip inductors.

• Korean Journal of Crystallography
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• v.12 no.2
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• pp.70-75
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• 2001

The purpose of this study is to investigate the effect of V₂O/sub 5/ addition on physical and magnetic properties of NiCuZn ferrite for multi-layer chip inductors. NiCuZn ferrite pastes doped with 0, 0.1, 0.3 and 0.5 wt% V₂O/sub 5/ were prepared and samples of ferrite sheets were prepared by the screen printing method. They were sintered at 870, 880, 890 and 900℃, and then their physical and magnetic properties were analyzed. After sintering at 870℃, the sintered density of the ferrite sheet doped with 0.5wt% V₂O/sub 5/ showed the highest value to 5.08g/cm³due to the best densification by the liquid phase sintering, while the microstructures of ferrite sheets doped with 0.1 and 0.3 wt% V₂O/sub 5/ showed and inhibited grain growth. Irrespective of the sintering temperature, the initial permeability of ferrite sheet doped with 0.5 wt% V₂O/sub 5/ was highest and after sintering beyond 880℃, the quality factor of 0.3 wt% V₂O/sub 5/-doped sample appeared to be highest.

• Electronics and Telecommunications Trends
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• v.10 no.3 s.37
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• pp.151-163
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• 1995

최근 이동통신, 위성통신 등 통신시스템의 급속한 발달과 더불어 마이크로파대에서 이용될 수 있는 통신기기의 개발이 시급히 요구되고 있다. 더우기 주파수자원의 활용범위가 고주파 광대역화되어 감에 따라 새로운 부품의 개발이 대두되고 있다. 그중 페라이트 자성체를 이용한 마이크로파 부품은 가용주파수 대역을 고주파화 및 광대역화할 수 있으므로 이동통신, 위성통신 시스템 등에 활용가능성이 새로이 제안되고 있다. 본 고는 자성체를 이용한 마이크로파 부품들인 칩인덕터, 박막인덕터, 정자파소자, 위상변위기 등의 개발현황에 대해 조사분석한 것이다.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.63-68
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• 2002

본 논문에서는 관통형 고주파 노이즈 필터(noise filter)를 설계하고, 제작하였다. 분포정수형(distributed constant type) 노이즈 필터는 세라믹 다층 구조(multi-layer)를 가지며, 기존의 노이즈 억압 방법인 칩 페라이트 비드, 3단자 커패시터 그리고 집중 정수형(lumped constant type) 노이즈 필터에 비해 신호의 왜곡이 적고, 고주파 노이즈 억압특성이 우수하다. 본 논문에서는 기존의 분포정수형 노이즈 필터에 관통형 via-hole을 삽입하는 새로운 구조를 제안하였다. 제작된 노이즈 필터는 100MHz의 차단 주파수, 700MHz~1700MHz에서 20㏈이상의 감쇠 특성을 나타내었다. 또한, 기존의 노이즈 필터의 단점인 방향성 덴 공정에 대한 민감도를 개선시킴으로써 양산성이 향상되었다.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.4
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• pp.57-64
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• 1995

Three models for the transformation of ferrite chip noise filter that has jagged type of electrode into cylinderical ferrite beadfilter were presented. The properties of filters were also calculated based on the proposed models. The measured properties of ferrite chip noise filter with jagged-type electrode fabricated with Ag electrode and Ni-Zn ferrite revealed that the model 3 was the best one to describe the behavior of filters. In particular, the calculated values of model 3 agreed well with measured ones as functions of electrode patterns and chip thickness. The present study showed that the properties of fiters could be designed by theoretical models and fabricated with required characteristics.

• Journal of the Microelectronics and Packaging Society
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• v.9 no.4
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• pp.47-53
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• 2002

In this study, two different (NiCuZn)-ferrite which were fabricated by using ultra-fine powders synthesized by the wet processing and conventionally commercialized powder, were investigated and compared each other in terms of the low temperature sintering and electromagnetic properties. Composition of x and w in $(Ni_{0.4-x}Cu_xZn_{0.6})_{1+w}(Fe_2O_4)_{1-w}$ were controlled as 0.2 and 0.03, respectively. The sintering temperature were $900^{\circ}C$ for ultra-fine powders by way of initial heat treatment and $1150^{\circ}C$ for commercialized powders. The (NiCuZn)-ferrite by ultra-fine powders showed love. sintering temperature than that of commercialized powders by over $200^{\circ}C$, and excellent electromagnetic properties such as the quality factor which is a important factor in the multi-layered chip inductor. In addition, characteristics of B-H hysteresis, crystallinity, microstructure and powder morphology were analyzed by a vibrating sample method(VSM), x-ray diffractometer(XRD), transmission electron microscope (TEM) and scanning electron microscope(SEM).

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.11a
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• pp.109-113
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• 2002

본 연구에서는 공침법에 의한 초미세분말을 이용하여 제조된 (NiCuZn)-ferrite와 건식법을 이용하여 제조된 (NiCuZn)-ferrite의 저온소결 특성 및 전자기적 특성을 상호 비교 분석하였다. 조성은 (N $i_{0.4-x}$C $u_{x}$Z $n_{0.6}$)$_{1+w}$(F $e_2$ $O_4$/)$_{1-w}$에서 x의 값을 0.2, w의 값은 0.03으로 고정하였고, 소결은 공침법으로 합성된 분말의 경우 초기열처리과정을 거쳐 최종적으로 90$0^{\circ}C$에서, 건식법의 경우 11$50^{\circ}C$의 온도에서 진행하였다. 그 결과, 공침법으로 제조된 (NiCuZn)-ferrite는 건식법으로 제조된 (NiCuZn)-ferrite보다 20$0^{\circ}C$이상 낮은 소결온도에서 높은 소결밀도 값을 가졌으며, 품질계수 등 칩 인덕터에서 중요한 요소인 전자기적 특성이 우수하게 나타났다. 또한, 공침법으로 합성된 페라이트는 분말의 초기열처리온도에 따라 최종소결 특성이 크게 변하였다. 그밖에 공침법과 건식법으로 합성한 (NiCuZn)-ferrite의 결정성, 미세구조들을 XRD, SEM, TEM을 이용하여 비교 고찰하였다.하였다.다.

• Korean Journal of Materials Research
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• v.13 no.8
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• pp.503-508
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• 2003

The purpose of this study is to investigate the effect of $V_2$$O_{5}$ addition on the Ag and Cu precipitation in the NiCuZn ferrite layers of 7.7${\times}$4.5${\times}$1.0 mm sized multi-layer chip inductors prepared by the screen printing method using 0∼0.5 wt% $V_2$$O_{5}$ -doped ferrite pastes. With increasing the $V_2$$O_{5}$ content and sintering temperature, Ag and Cu oxide coprecipitated more and more at the polished surface of ferrite layers during re-annealing at $840^{\circ}C$. It was thought that during the sintering process, V dissolved in the NiCuZn ferrite lattice and the Ag-Cu liquid phase of low melting point was formed in the ferrite layers due to the Cu segregation from the ferrite lattice and Ag diffusion from the internal electrode. During re-annealing at $840^{\circ}C$, the Ag-Cu liquid phase came out the polished surface of ferrite layers, and was decomposed into the isolated Ag particles and the Cu oxide phase during the cooling process.