레이저 어블레이션에 의한 $(Pb,La)TiO_3$ 박막의 제작

박정흠,김준한,이상렬,박종우,박창엽,Park, Jeong-Heum,Kim, Joon-Han,Lee, Sang-Yeol,Park, Chong-Woo,Park, Chang-Yub 한국전기전자재료학회 1998 전기전자재료학회논문지 Vol.11 No.2

$(Pb_{0.72}La_{0.28})Ti_{0.93}O_3(PLT(28))$ thin films were fabricated by pulsed laser deposition. PLT films deposited on $Pt/Ti/SiO_2/Si$ at $600^{\circ}C$ had a preferred orientation in (111) plane and at $550^{\circ}C$ had a (100) preferred orientation. We found that (111) preferred oriented films had well grown normal to substrate surface. This PLT(28) thin films of $1{\mu}m$ thickness had dielectric properties of ${\varepsilon}_r$=1300, dielectric $loss{\fallingdotseq}0.03 $. and had charge storage density of 10 [${\mu}C/cm^2$] and leakage current density of less than $10^{-6}[A/cm^2]$ at 100[kV/cm]. These results indicated that the PLT(28) thin films fabricated by pulsed laser deposition are suitable for DRAM capacitor application.

적층형 마이크로파 소자용 BiNbO4 유전체 세라믹스의 유전특성

박정흠,장낙원,윤광희,최형욱,박창엽 ( Jeong Heum Park,Nak Won Jang,Kwang hee yoon,Hyung Wook Choi,Chang Yub Park ) 한국전기전자재료학회 1996 전기전자재료학회논문지 Vol.9 No.9

2.45GHz RFID용 원형편파안테나의 설계 및 제작

박정흠,Park, Jeong-Heum 대한전자공학회 2005 電子工學會論文誌 IE (Industry electronics) Vol.42 No.4

In this paper, the single coaxial fed and circularly polarized patch antenna for the RFID system in 2.45GHz ISM band has been fabricated. The simulation by HFSS, electro-magnetic field simulator was executed in order to decide the location of feed which is difficult to be analysed. The simulated result has the same tendency as the measured one in the view of input impedance with the variation of feed location. VSWR of fabricated antenna is low($\leq$1.2) even in comparatively high dielectric loss epoxy substrate(FR4), and this value is enough for the application of RFID reader antenna. 본 논문에서는 RFID 시스템에서의 응용을 위해, 2.45GHz ISM대역에서 동작하는 단일동축급전 원편파 패치 안테나를 제작하였다. 안테나 제작에 앞서서, 일반적인 식으로 예측하기가 어려운, 최적의 급전점 위치를 확인하기 위해, HFSS 전자계 시뮬레이터를 이용하여 모의실험하였다. 이후, 실제 안테나를 제작하여 급전점의 위치에 따른 패치 안테나의 입력임피이던스를 측정한 결과, 모의실험결과와 일치하는 경향을 보였다. 제작된 안테나의 특성은 유전손실이 상대적으로 큰 에폭시 기판(FR4)에서도 VSWR이 1.2이하인 우수한 특성을 가졌고, 이 결과는 RFID 리더 안테나의 응용에 충분한 값이다.

재귀원형군의 강한 해밀톤 성질

박정흠,Park, Jeong-Heum 한국정보과학회 2001 정보과학회논문지 : 시스템 및 이론 Vol.28 No.8

이 논문은 재귀원형군 G(2$^{m}$ , 2$^{k}$ )의 강한 해밀톤 성질을 그래프 이론적 관점에서 고찰한다. 재귀원형군은 [9]에서 제안된 다중 컴퓨터의 연결망 구조이다. G(2$^{m}$ , 2$^{k}$ )가 임의의 정점 쌍 ν, $\omega$를 잇는 길이 ι인 경로를 가지는가 하는 문제를 고려하여, (a) G(2$^{m}$ , 2$^{k}$ )는 ι$\geq$d(ν, $\omega$)을 만족하는 모든 ι에 대해서 길이 ι인 경로를 가지며, (b) G(2$^{m}$ , 4)는 ι$\geq$d(ν, $\omega$)+2인 모든 길이의 경로를 가지며, (c)G(2$^{m}$ , 2$^{k}$ ), k$\geq$3은 길이 d(ν, $\omega$)+2$^{k}$ -3인 경로를 가지지 않는 정점 쌍이 있음을 보인다. 여기서, d(ν, $\omega$)는 ν와 $\omega$ 사이의 거리이다.

마이크로파대에서의 강유전 박막 유전 특성 평가

박정흠,Park, Jeong-Heum 한국전기전자재료학회 2004 전기전자재료학회논문지 Vol.17 No.10

In this study, ferroelectric (Ba,Sr)TiO$_3$ and high temperature superconductor YBCO thin films were fabricated by PLD (Pulsed Laser Deposition) method and tuneable bandstop filters were implemented with two different IDC(Interdigital Capacitance) gap patterns, 20${\mu}{\textrm}{m}$ and 30${\mu}{\textrm}{m}$ using these two thin film layers. The resonant frequency was changed by DC bias voltage. By comparing measured results with simulation, the dielectric properties of ferroelectric thin film have been extracted. The permittivity was 820 ~ 900 at 30 K and had an acceptable error range but the loss tangent had a great difference, 0.018 in 30${\mu}{\textrm}{m}$ IDC gap pattern and 0.037 in 20 ${\mu}{\textrm}{m}$.

마이크로파 무선전력전송을 위한 렉테나 설계와 구현

박정흠,Park, Jeong-Heum 한국조명전기설비학회 2006 조명·전기설비학회논문지 Vol.20 No.6

본 논문에서는 마이크로파를 이용한 무선전력전송시스템을 구현하기 위해 2.45[GHz] 마이크로파를 수신하여 직류전력으로 변환하는 렉테나를 설계, 구현하고, RF-DC변환효율을 높이기 위한 임피던스 매칭 및 튜닝 방법을 제시하였다. 구현된 렉테나는 넓은 Open Stub를 사용하여, 쉽게 튜닝이 가능하며, 정류회로의 RF-DC변환효율은 5[dBm]입사전력에 대하여, 최대 59[%]를 얻을 수 있었다. 제작된 패치안테나와 정류회로를 이용하여 소전력무선전송시스템을 구현한 결과, 송수신거리가 1[m]떨어진 거리에서 2.2[V], 1.5[mW]의 직류전력송신이 이루어졌으므로, 소전력 디지털시스템의 운용에 적용가능한 값을 얻을 수 있었다. In this paper, the rectenna converting 2.45[GHz] microwave into DC power is designed and fabricated for wireless power transmission using microwave and the methode for impedance matching and tuning are proposed in order to maximize RF-DC conversion efficiency. The fabricated rectenna can be easily tuned by using a broad open stub and has the RF-DC conversion efficiency up to 59[%] when the 5[dBm] input power is applied. The 2.2[V], 1.5[mW] DC level, in the 1[m] distance between the transmitter and the receiver can be obtained and this value is avaliable in the small power digital system.

유도성 전력 전송 시스템에서의 코일 간 상호 인덕턴스 모델링

박정흠(Jeong-Heum Park) 한국조명·전기설비학회 2018 조명·전기설비학회논문지 Vol.32 No.6

Among the various methods of wireless power transmission using the near and field of electromagnetic energy, the most realistic method is the inductive power transfer (IPT) method. This method has a higher transmission efficiency and minimizes the influence of electromagnetic waves on the human body as compared with other methods, and has attracted attention as a method most likely to be commercialized in wireless charging of electric vehicles. In this paper, the coupling coefficient and mutual inductance between the Tx-Rx loop coils are modeled and the efficiency of the system is calculated using mathematical analysis in the near field using IPT system. As a result, it is confirmed that the measured value of efficiency at actual IPT system is in good agreement with the calculated one, so this analysis method can be applied to the design and the optimization of the distance of the coil at the IPT system for wireless charging of electric vehicles.

해상 레이더와 스마트 기기 간 무선 인터페이스를 이용한 스마트 레이더 시스템에 관한 연구

박정흠(Jeong-Heum Park) 융복합지식학회 2016 융복합지식학회논문지 Vol.4 No.2

연구에서는 상용 레이다의 이미지 정보와 물표 접근에 따른 경보 신호를 승조원의 스마트 기기에 무선으로 전송하는 스마트 레이더 시스템을 구성하였다. 이 시스템에 의해 승조원은 선상의 어떤 위치에서도 작업 중에 레이더 화면을 모니터할 수 있고 경보에 대한 즉각적인 조치를 취할 수 있도록 하였다. 경보시스템의 주요 성능으로, 영상정보 업데이트 30[FPS], 실시간 이미지 전송지연시간 1초 이하, 경보발생지연시간 0.3초 이하를 구현하였다. 본 연구의 결과물을 통하여 거의 모든 승조원이 소지하고 있는 고성능의 모바일 기기를 활용하여 선박 및 해상에서 안전 및 관리의 효율화를 기하는 응용의 하나를 제시할 수 있었다. In this study, we developed the smart radar system to send the image information of a commercial radar to the main control unit and wirelessly transmit the stored information to the smart device. Also, when a target object approaching, the system pushes the alarm signal to the crew"s smart devices By this way, the crew can continuously monitor the radar display at any places in a boat and immediately execute the proper treatment. The implemented system shows the major performance parameters as the display update rate 30[FPS], real time image transmission delay time less than 1[sec] and alarm invoke delay time at smart device less than 0.3[sec]. Through the results of the present study, we can propose the application that make the effective marine safety management using the mobile devices almost all crew members take. At the time the ship electronic equipment market grows rapidly, the new proposed smart radar system will provide the platform for the marine smart network and elaborate ship movement control system.

자계 공진 방식의 무선전력전송 장치를 이용한 교류 전력 직접 인가에 의한 LED 조명기기 효율에 관한 연구

박정흠(Jeong-Heum Park) 한국조명·전기설비학회 2013 조명·전기설비학회논문지 Vol.27 No.10

In this paper, wireless power transfer system using the magnetic resonance was designed and applied to LED lighting for implementation of wireless lighting. This lighting was made by the converted DC driving type and the direct AC driving type. In the former, transferred AC power was rectified into DC and regulated to the specified voltage value, which leads to produce the loss at the rectifying and regulating circuit. In the latter, wireless-transferred AC power was directly applied to LED, which get rid of the loss derived from the additional circuit. For the efficiency-comparison between the former and the latter, the power at each stage was measured when the same optical output radiated from LED lighting part. The result revealed that the direct AC driving type had 18% higher efficiency than the DC driving type and confirmed that LED lighting using magnetic resonance wireless power transfer system can be efficient by direct AC power supply. And the direct AC driving type had the simple circuit structure and the simple LED lighting formation, so this can leads to various application.

공진 코일의 크기와 부하 저항이 자계 공명 무선 전력 전송 장치의 전달 효율에 주는 영향에 관한 연구

박정흠(Jeong-Heum Park) 한국조명·전기설비학회 2012 조명·전기설비학회논문지 Vol.26 No.7

In this paper, the wireless power transfer system using the magnetic resonance was designed and the effect of resonant coil radius and load resistance to this system was analyzed by the circuit analysis method. As a result, the calculated transmitted-power is similar to measured one, and the coil size has a small effect to the coupling coefficients in the resonant frequency band. In addition, the fact that the calculated transmitted-power according to the source frequency is similar to measured one confirms that the circuit analysis methode in this paper is valid. The input side transmission efficiency η<SUB>i</SUB> including only the loss in the power transfer circuit is almost 90[%] with the large coil in the 10[cm] transfer distance, and 65[%] with the small coil in 1[cm]. The source side transmission efficiency η<SUB>s</SUB> is 30~40[%] at both coil when load resistance below 4.7[Ω] has been connected. Considering that the maximum η<SUB>s</SUB> is 50[%], this is valid in the practical applications.