• Journal of Electrical Engineering and Technology
• /
• 제4권4호
• /
• pp.531-537
• /
• 2009

Lightning has a broad frequency spectrum from DC to a few MHz. Consequently, the high frequency performance of grounding systems for protection against lightning should be evaluated, with the distributed parameter circuit model in a uniform soil being used to simulate grounding impedances. This paper proposes a simulation method which applies the distributed parameter circuit model for the frequency-dependent impedance of vertically driven ground rods by considering multi-layered soil structures where ground rods are buried. The Matlab program was used to calculate the frequency-dependent ground impedances for two ground rods of different lengths. As a result, an increase of the length of ground rod is not always followed by a decrease of grounding impedance, at least at a high frequency. The results obtained using the newly proposed simulation method considering multi-layered soil structures are in good agreement with the measured results.

• 융합신호처리학회논문지
• /
• 제2권2호
• /
• pp.111-118
• /
• 2001

본 연구에서는 패턴 인식용 다층 퍼셉트론 신경망을 순수 디지털 논리회로 모델로 구현할 수 있도록 새로운 논리뉴런의 구조, 디지털 정형 다층논리신경망 구조, 그리고 패턴인식의 응용을 위한 다단 다층논리 신경망 구조를 제안하고, 또한 제안된 구조는 매우 단순하면서도 효과적인 증가적인 가법적(Incremental Additive) 학습알고리즘이 존재함을 보였다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 추계종합학술대회 논문집(2)
• /
• pp.341-344
• /
• 2000

Several new via structures in printed circuit boards are proposed, fabricated and characterized in RF regime. The new structure with a larger inductance component in the bottom layer shows 3㏈ improvement over the conventional structure. The ADS simulation with model parameters extracted from 3D fie]d solver matches with the characterization of these vias

• 한국전기전자재료학회논문지
• /
• 제19권12호
• /
• pp.1099-1105
• /
• 2006

In this paper, the equivalent circuit model of a Rosen-type multilayer piezoelectric transformer(MPT) has been proposed based on the Mason's equivalent circuit model and the principle of single layer piezoelectric plate. From the piezoelectric direct and converse effects, the symbolic expressions between the electric inputs and outputs of the MPT have been derived from the equivalent circuit model. A simplified equivalent circuit model of the MPT whose driving part has a single input form has been proposed. The symbolic expressions of the driving part have been derived from the simplified equivalent circuit model and the model was compared with the multi-input equivalent circuit model through the simulation. In the comparisons between the simulation results and the experimental data, output voltage is 630 Vp-p in case of 11-layered MPT and 670 Vp-p for 13-layered MPT over the experiment range. As the load resistance increases, output voltage increases and saturates over $300k{\Omega}$ and the resonant frequency changes from 102 kHz to 103 kHz. The simulation and the experimental results agree well over different load resistances and frequencies.

• 대한전자공학회논문지SD
• /
• 제47권12호
• /
• pp.55-67
• /
• 2010

고다층 배선 기판에 형성된 개방 스터브(open stub)를 제거한 후면드릴가공홀(Back-Drilled-Hole, BDH)과 일반적인 구조인 관통홀(Plated-Through-Hole, PTH) 구조의 전기적 특성에 대한 분석을 하였으며, 고속 선호를 부품 실장면으로부터 내층의 스트립라인으로 전송하기 위해 비아홀의 급전 길이가 가장 긴 전송층을 선택하였다. 10 GHz의 광대역 주파수 내에서 실험계획법(DOE, design of experiment)을 적용하여 비아홀 구조 내에 외층과 급전층 사이의 비아홀의 길이, 접지층에 형성된 천공(anti-pad)의 크기와 급전층에 형성된 패드 (pad)의 크기가 최대 반사 손실 반전력 주파수와 삽입 손실에 미치는 영향을 분석하였다. 이로 부터 거시적 모델(macro model)을 위한 회귀 실험식을 추출하여 실험 결과와 비교 평가하였고, 실험 영역 외에서도 측정 결과와 5% 이내의 오차를 보이고 있음을 확인하였다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
• /
• pp.653-656
• /
• 2002

In this paper, we present the simulation results of multi-layer VCO(voltage controlled oscillator), which is composed of resonator, oscillator, and buffer circuit, using EM simulator and nonlinear RF circuit simulator. EM simulator is used for obtaining the EM(Electromagnetic) characteristics of conductor pattern as well as designing the multi-layer VCO. Obtained EM characteristics were used as real components in nonlinear RF circuit simulation. Finally the overall VCO was simulated by the nonlinear RF circuit simulator. The material for the circuit pattern was Ag and the dielectric was DuPont 951AT, which will be applied for LTCC process. The structure of multi-layer VCO is constructed with 4 conducting layer. Simulated results showed that the output level was about 4.5 [dBm], the phase noise was -104 [dBc/Hz] at 30 [kHz] offset frequency, the harmonics -8 dBc, and the control voltage sensitivity of 30 [MHz/V] with a DC current consumption of 9.5 [mA]. The size of VCO is $6{\times}9{\times}2$ mm(0.11[cc]).

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 하계학술대회 논문집
• /
• pp.680-683
• /
• 2001

The output characteristics of step-down piezoelectric transformer is changed by a structure of layers. In this paper, we simulated output characteristics of multi-layer piezoelectric transformers with variation of output layers. Also, fabricated piezoelectric transformers were compared with simulated data. From simulated piezoelectric transformers, the output voltage decreased with increasing number of layers. From these results, piezoelectric transformers were made and the output electrical power of the transformers was measured at resonance frequency and at other frequency. The electrical power of transformers was measured on each transformer's resonance mode. However, measured value of 12-layed transformer's output power was smaller than that of 6-layered transformer's one. It is supposed that internal capacitance and reactance of the piezoelectric transformer's were effected in this result. Therefore we need to connect other road resistance and capacitance in output circuit, in order to increase electrical power of transformers.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회A
• /
• pp.321-325
• /
• 2007

Recently, demands on thin multi-layer printed circuit boards(PCB) have been rapidly increased with broad spread of personal portable digital appliances such as multi-media. In case of mobile phone, however, the fact that PCBs have low flexural strength might cause defects. The purpose of this study is to improve the flexural strength by substituting the well-known GFRP(glass fiber reinforced plastic) for CFRP(carbon fiber reinforced plastic). Firstly, finite element simulation was carried out using ABAQUS to find out a unique CFRP layer that has a role to sustain the applied forces mainly in PCB. Secondly, three point bending tests were conducted with the newly designed CFRP PCB model to verify the improvement of the flexural strength. Consequently, it is shown that PCB layered with the CFRP on both outer sides of the board can be used to improve the flexural strength effectively.

• 공업화학
• /
• 제21권3호
• /
• pp.291-294
• /
• 2010

최근 고효율 염료감응형 태양전지를 위한 다층구조의 $TiO_2$ 전극에 대한 연구가 관심을 받고 있다. 본 연구에서는 입자의 크기가 작고 큰 $TiO_2$로 이루어진 다층구조의 $TiO_2$ 전극에 대해 연구하였다. 나노구조를 갖는 $TiO_2$ 분말은 $TiCl_4$를 가수분해하여 합성하였다. 크기가 7.6 nm 및 18 nm인 $TiO_2$ 분말은 소성온도를 조절하여 얻었다. 다층구조를 갖는 $TiO_2$ 전극이 단락전류(Jsc)에 큰 영향을 미치는 것을 확인하였으며, 또한 다층구조를 갖는 $TiO_2$ 전극이 각각의 입자만을 사용한 염료감응형 태양전지 보다 변환효율이 증가함을 확인하였다.

• 조명전기설비학회논문지
• /
• 제24권4호
• /
• pp.73-80
• /
• 2010

접지임피던스는 접지전극의 크기를 증가시켜도 낮아지지 않고, 토양의 특성과 주파수 조건에 따라 접지 임피던스가 최소값을 보이는 접지전극의 길이가 존재하며, 이 접지전극의 길이를 각 토양 특성과 주파수에 따른 임계길이라 한다. 본 논문에서는 대지구조의 조건을 고려하는 새로운 분포정수회로모델을 제안하였으며, 새로이 제안된 해석모델을 적용하여 MATLAB프로그램으로 수직접지전극의 임계길이와 접지임피던스를 해석하였다. 그 결과, 수직접지전극의 임계길이와 접지임피던스의 주파수의존성에 대한 대지구조의 영향이 크며, 접지시스템의 최적 설계를 위해서는 대지구조를 고려하는 것이 바람직한 것으로 밝혀졌다.