• 한국산학기술학회논문지
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• 제11권9호
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• pp.3435-3440
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• 2010

표면탄성파를 이용한 RF소자의 성능을 단순히 작동 유무로만 평가할 수 있는 전기적인 성능 평가방법과 달리 위치에 따른 표면탄성파의 형성 정도를 실시간으로 검사할 수 있는 광학적 방법을 제시하였다. 광학적 방법을 이용한 표면 탄성파의 측정 조건과 한계를 제시하였고 간섭 및 회절 현상을 이용하여 RF신호의 입력 유무에 따른 광학적 해석을 하였다. 단일 모드 레이저를 이용하여 중심 주파수가 105MHz인 중계기 필터의 동작을 실험적으로 측정하고 이론적으로 분석하였다. 본 논문에서는 다기능 서비스를 제공하는 복합 주파수 RF 모듈의 고품질화를 위한 방법으로 표면탄성파의 에너지 분포를 시각화하고 실시간으로 평가할 수 있는 광학적 방법을 제시하였다.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.140-144
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• 2003

To investigate failure analysis of surface acoustic wave (SAW) filter for radio frequency, high temperature storage test was carried out. The failure criteria were insertion loss at passband and rejection level at stopband. As a result, the insertion loss at passband increase about 4 dB was due to damages of interdigital transducer (IDT). That is caused by poor adhesion between metal electrode(AI) and piezoelectric substrate and defects on a manufacturing process. This result indicates that good adhesion between electrode and ceramic substrate is important factor And also we investigated the demage factors of electrode. Screen possible of saw filter using high temperature storage test(HTOL) in the manufacturing phase be presented.

• 한국음향학회지
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• 제3권2호
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• pp.13-22
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• 1984

A surface acoustic wave signal processing device using the silicon surface state is presented and shown capable of storing a reference signal and later correlating another signal with the stored reference. The device memory consists of the storage of the spatial 2k pattern of an acoustic wave as stored charges in the surface state of silicon surface. Results of experiments are presented which characterize the operation of device. Simpliied models for charging process and nonlinear acoustoelectric interactions based on consideration of single surface state at the surface of silicon The validity of simplified model has been qualitatibely confirmed with experimental results and the application of this device to aprogrammable matched filter of communication is considered.

• 한국광학회지
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• 제11권6호
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• pp.423-428
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• 2000

방향성 결합 구조의 음향파 도파로를 이용한 편광모드 변환형 파장가변 광 필터를 LiNbO$_3$ 와 Ti 이중 확산 공정기술을 이용하여 제작하였다. 균일 결합구조형 AOTF의 부모드의 크기를 두 음향파 도파로의 방향성 결합형 가중 결합 원리를 이용하여 8 dBwjd도 추가적으로 억제시킬 수 있었다. 1551.6mm 파장의 TE, TM 입사 편광모드와 173.58MHz, 17.78mW RF 구동신호각각에 대해서 -12.68dB 부모드 억압과 90% 변환효율이 측정되었다. 파장변화율과 통과 대역폭은 각각 8.86nm/ MHz, 1.7nm로 측정되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1981년도 하계 학술회의초록집
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• pp.157-159
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• 1981

• 한국전기전자재료학회논문지
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• 제14권5호
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• pp.435-443
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• 2001

As power durable RF SAW filters, AL-(0∼2wt%)Cu alloy multi-layered thin electrodes were deposited on 42° LiTaO$_3$ piezoelectric substrates by magnetron sputtering process, and then ladder-type RF SAW filters, satisfying the electrical specification of CDMA transmission band, were fabricated through optimizing SAW resonator structures. The temperature of film electrodes in SAW filter was increased with RF power, and reached the maxima to cause a failure of SAW filters at the cut-off frequencies of the RF filter band. As RF power increases, the electrodes of Al-Cu alloy showed higher power durability than that of pure Al. The multi-layer laminated film of Al-1wt.% Cu/Cu/Al-1wt%Cu resulted in the best power durability up to 4W of RF power. Every film electrode, however, was destroyed within seconds whenever applying a critical RF power to SAW filters, regardless of the composition and structure of film electrodes. The breakdown of film electrodes under FR power seems to believe due to the fatigue of electrodes caused by repetitive cyclic stress of surface acoustic wave, which is amplified as RF power increases.

• 대한전기학회논문지
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• 제41권5호
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• pp.502-507
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• 1992

To improve temperature stability, 0.05Pb(SnS11/2TSbS11/2T)OS13T-0.35PbTiOS13T-0.60PbZrOS13T+0.4[wt%]MnO S12T piezoelectic ceramics were manufactured with the addition of CrS12TOS13T by Hot Press method. And the SAW delay line was fabricated and effects of CrS12TOS13T to the propagation characteristics of SAW was investigated, and the SAW filter was fabricated on C4 specimen added by 0.2[wt%] CrS12TOS13T whose propagation characteriatics of surface acoustic wave were the bast and its frequency characteristics was investigated. Electromechancal coupling factor(kS1sTS02T) was 3.11[%] and its temperature coefficient of the center frequency(CS1foT)was -21.27[ppm/$^{\circ}C$] in C4. The 31[MHz]]SAW IF filter of C4 scarcely had diffraction phenomena and therefore it was proper.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 센서 박막재료 반도체 세라믹
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• pp.141-144
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• 2003

This study proposes ZnO thin film as a piezoelectric material for SAW (surface acoustic wave) filter. The ZnO thin film with thickness $2.6{\mu}m$ was deposited (0001)-oriented sapphire by RF magnetron sputtering technique. IDTs (inter-digital transducers) electrodes were patterned upon SAW filter mask with solid finger structure unapodized using lift-off method on ZnO piezoelectric thin film. SAW propagation velocity was measured with the center frequency by HP 8753C network analyzer. A fabricated ZnO SAW filter exhibited a high propagation velocity of 5433 $^m/s$ and relatively insertion loss of -53.391dB at $\lambda=80{\mu}m$. The side-lobe attenuation of the center frequency was about 17dB. When the wavelength was $80{\mu}m$ $(\lambda/4=20{\mu}m)$, the center frequency was 67.907 MHz. $k^2$ (electromechanical coupling coefficient) was 15.84 %.

• 한국항행학회논문지
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• 제12권2호
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• pp.139-145
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• 2008

최근 60GHz 대역의 millimeter wave 를 이용하는 통신 시스템에 관한 연구가 활발히 진행되고 있으며 새롭게 정의된 57~64GHz의 ISM 대역에 대한 관심이 집중되고 있다. 국내를 비롯한 미국, 일본, 유럽 등에서도 millimeter wave 를 이용하는 근거리 통신에 대한 연구가 진행 중이다. 그 중 IEEE 802.15.3c 표준화는 근거리에서 높은 전송 속도를 지원하기 위해 OFDM (Orthogonal Frequency Division Multiplexing) 방식의 시스템을 제안하고 있다. 하지만 OFDM 방식은 PAPR (Peak-to-Average Power Ratio) 이 발생하는 문제점을 가지고 있으며, PAPR 문제는 신호가 A/DC와 D/AC 그리고 전력 증폭기와 같은 비선형 소자를 통과할 때 심각한 왜곡을 발생시켜 전송 시스템의 성능이 저하된다. 본 논문에서는 PAPR 문제를 해결하기 위하여 Sine Soft Clipping (SSC) 기법을 제안하고, SAW (Surface Acoustic Wave) Filter와 전력 증폭기를 적용하여 IEEE 802.15.3c OFDM WPAN 전송 시스템의 PAPR, CCDF, PSD, BER 성능을 분석하였다.

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 동계학술발표회 논문집
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• pp.459-460
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• 2009

In this study, surface structure and near-field distribution of a surface acoustic wave filter were measured with both reflection mode and collection mode near-field scanning optical microscopes, and there results were compared with each other.