• Journal of information and communication convergence engineering
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• 제14권3호
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• pp.184-190
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• 2016

We present experimental demonstrations of electromagnetic bandgap (EBG) structures for the wideband suppression of radiated emissions from a power bus in high-speed printed circuit boards (PCBs). In most of the PCB designs, a parallel plate waveguide (PPW) structure is employed for a power bus. This structure significantly produces the wideband-radiated emissions resulting from parallel plate modes. To suppress the parallel plate modes in the wideband frequency range, the power buses based on the electromagnetic bandgap structure with a defected ground structure (DGS) are presented. DGSs are applied to a metal plane that is connected to a rectangular EBG patch by using a via structure. The use of the DGS increases the characteristic impedance value of a unit cell, thereby substantially improving the suppression bandwidth of the radiated emissions. It is experimentally demonstrated that the DGS-EBG structure significantly mitigates the radiated emissions over the frequency range of 0.5 GHz to 2 GHz as compared to the PPW.

• 한국정밀공학회지
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• 제20권8호
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• pp.76-85
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• 2003

In this paper, a technical method for removing the solder from PCBs has been proposed to simplify the pulverizing process and to get higher quality of materials for recycling of the electronic parts in the Printed Circuit Boards (PCBs). There are several techniques to remove the solder from PCB, such as physical and chemical method, vibration, suction and blowing and so on. Among them, the suction technique turned out the best method by investigation. In the suction method, there are three variables for removing the solder. They are a temperature of the thermal wire, a velocity of moving PCB and a gap between PCB and thermal wire. To find the optimal variables for the system, an experiment has been conducted by a trial and error method. The optimal variables were found $220^{\circ}C$ of temperature, 11.58mm/s of velocity, 10mm of gap (A gap between suction hole and bottom of PCBs is 5mm). The result of the experiment shows that 50% of the solder were removed.

• 한국표면공학회지
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• 제32권3호
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• pp.289-296
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• 1999

The integration of the LSI has been greatly improved and the circuit patters on the LSI are becoming finer line and pitch. The high-density electronic packaging technology is improved. In order to realize the high-density packaging technology, the density of the circuit wiring of the printed circuit boards have also been more dense. The build-up process multilayer printed circuit board technology have a lot of vias, possibilities of the finer conductor wirings and have a freedom of capabilities of wiring design. The build-up process printed circuit boards have the wiring rules which are the pattern width: $100-20\mu\textrm{m}$, the via hole diameter: $100-50\mu\textrm{m}$. There three kinds of build-up processes as far materials and hole drilling. In this paper, the recent technology trends of the build-up printed circuit board technologies are described.

• 한국정밀공학회지
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• 제21권8호
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• pp.120-128
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• 2004

The impulse between launch vehicle and atmosphere can generate a lot of noise and vibration during the process of launching a satellite. Structurally, the electronic equipment of a satellite consists of an aluminum case containing PCB. Each PCB has resistors and IC. Noise and vibration of the wide frequency band are transferred to the inside of fairing, subsequently creating vibration of the electronic equipment of the satellite. In this situation, random vibration can cause malfunctioning of the electronic equipment of the device. Furthermore, when the frequency of random vibration meets with natural frequency of PCB, fatigue fracture may occur in the part of solder joint. The launching environment, thus, needs to be carefully considered when designing the electronic equipment of a satellite. In general, the safety of the electronic equipment is supposed to be related to the natural frequency, shapes of mode and dynamic deflection of PCB in the electronic equipment. Structural vibration analysis of PCB and its electronic components can be performed using either FEM or vibration test. In this study, the natural frequency and dynamic deflection of PCB are measured by FEM, and the safety of the electronic components of PCB is evaluated according to the results. This study presents a unique method for finite element modeling and analysis of PCB and its electronic components. The results of FEA are verified by vibration test. The method proposed herein may be applicable to various designs ranging from the electronic equipments of a satellite to home electronics.

• 전기전자학회논문지
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• 제20권4호
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• pp.416-419
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• 2016

전자 회로의 집적도와 동작 주파수가 증가함에 따라 신호 전달 특성을 향상시키는 것이 중요하다. 본 논문에서는 인쇄 회로 기판에서 패드의 곡률 변화에 따른 신호 전달 특성을 분석하였다. 시뮬레이션 결과, 곡률이 커질수록 신호 전달 특성은 개선되었고, 전송선로의 두께가 얇을수록 곡률 변화에 더 적은 영향을 받으며, 길이가 짧을수록 곡률 변화에 더 큰 영향을 받는 것을 확인할 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.621-624
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• 1999

Metalization technology of the fine patterns by electroless plating is required in place of electrodeposition as high-density printed boards(PCR) become indispensable with the miniaturization of electronic components. Electroless nickel plating is a suitable diffusion barrier between conductor meta1s, such as Al and Cu and solder is essetional in electronic packaging in order to sustain a long period of service. Moreover, Electroless nickel has particular characteristics including non-magnetic property, amorphous structure. wear resistance, corrosion protection and thermal stability In this study fundamental aspects of electroless nickel deposition were studied with effort of complexeing agents of different kinds. Then the property of electroless deposit are controlled by the composition of the deposition solution the deposition condition such as temperature and pH value and so on. the characteristics of the deposits has been carried out.

• 한국비블리아학회지
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• 제14권2호
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• pp.159-178
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• 2003

본 연구는 대학도서관에서 제공하는 전자게시판 중 자유게시판, Q＆A, FAQ, 참고질의 응답의 4가지 유형의 참고서비스를 대상으로 게재되는 질문의 유형과 내용을 분석함으로써 서비스 유형별 특성을 조사하고 이용자의 정보요구를 파악하였다. 분석한 결과, 4가지 서비스의 유형에 따라 질문유형별 차이를 발견하지 못하였다. 모든 서비스에서 안내형 질문이 가장 많았으며, 주제형 질문은 미미한 것으로 나타났다. 분석결과를 토대로 4가지 유형별 서비스에 대한 발전방안을 제시하였다: 서비스 유형에 대한 메뉴명칭의 표준화, 서비스 접근이 용이한 메뉴 배치, 각 서비스에 적합한 성격 명시, 내용검색기능과 응답기능을 첨가하는 구조개선, 질문작성 양식의 제안, 전자참고서비스의 전담부서 및 전담자배치, 정책마련, 홍보강화를 제안하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(1)
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• pp.269-272
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• 2004

Printed circuit boards (PCB) replaced conventional wiring in most electronic equipment I, reducing the size and weight of electronic equipment while improving reliability, uniformity, precision and performance. PCB is used in all kinds of electronic products because they can be mass-produced with very high circuit density and also enable easier trouble-shooting. This paper presents the analyses of the patent information of Build-up PCB which is seen as the most promising solution, as its substrate supports multi-level packaging, thinner board profiles and smaller pitches.

• 한국표면공학회지
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• 제49권6호
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• pp.477-485
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• 2016

As expensive and valuable metals being used in electronic and semiconducting industries are abandoned as industrial wastes after use of them, it is required to recover them from e-wasted electronics parts. Gold which is used for printed circuit boards or electronic equipments, accessories, etc., is one of e-Wasted materials and recently indium, gallium, zirconium, cobalt, molybdenum and lithium are bacome valuable metals to be recovered from the e-wastes. Since the amount of precious metals is now being faced with scarcity, lean too much on area and instability of supply, and industrial demands are rapidly increasing every year, it becomes more important to recover the valuable metals from the industrial wastes. In this review, we introduced technologies and research trend of the recovery processes of valuable metals from the e-wastes in high-tech devices over the world.

• 한국전자통신학회논문지
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• 제12권6호
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• pp.1035-1042
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• 2017

본 논문에서는 복잡한 전관방송 장비와 케이블을 용이하게 운용하고, 확장 및 증설할 수 있도록 전력선 통신을 이용한 전관방송 시스템을 개발하였다. 전력선 통신 기반 전관방송 시스템은 디지털 스트리밍 변조 방식을 적용한 제어 보드와 스피커 보드로 구현되었으며, 오디오 최대 출력, 오디오 채널 응답 시간, 오디오 출력 SNR, 그리고 오디오 출력 THD+N에 대한 성능 측정을 실시하여 만족스러운 결과를 확인할 수 있었다.