• 제목/요약/키워드: Quality Factor(Q)

검색결과 462건 처리시간 0.031초

Cobalt (Co) Electrode FBAR Devices Fabricated on Seven-Layered Bragg Reflectors and Their Resonance Characteristic

  • Mai Linh;Munhyuk Yim;Kim, Dong-Hyun;Giwan Yoon
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2003년도 추계종합학술대회
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    • pp.381-384
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    • 2003
  • In this paper, cobalt (Co)-electrode FBAR devices fabricated on seven-layered Bragg Reflectors are presented along with their resonance characteristics. ZnO films are used as the resonating material in FBAR devices where the Co electrode is 3000$\AA$ thick. All processes are preformed in an RF magnetron sputtering system. As a result of characterization, the resonance characteristics are observed to depend strongly on the quality of ZnO film and Bragg Reflectors. In addition, the FBAR devices with W/SiO$_2$ reflectors show good resonance characteristics in term of return loss and quality-factor (Q-factor).

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High-Q factor ZnO-based Film Bulk Acoustic Resonator Devices

  • Yoon, Gi-Wan;Mai, Linh
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2008년도 추계종합학술대회 B
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    • pp.61-65
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    • 2008
  • In this paper, we studied a ZnO-based film bulk acoustic resonator (FBAR) device fabricated on a specially designed multi-layerd Bragg reflector part. Very thin chromium adhesion layers (0,03um thick) were additionally deposited to improve the quality of the Bragg reflector and some thermal treatments were performed to improve the resonant characteristics of the device. At the operating frequency of ${\sim}2.7GHz$, excellent resonant characteristics were observed in terms of return loss and quality factor, and effective electromechanical coupling coefficient. These findings are expected to be highly promising and effective for improving the performance of the FBAR devices at high frequency.

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Thermal Improvements for 2.75 GHz-FBAR Devices

  • Mai, Linh;Lee, Jae-Young;Pham, Van-Su;Kabir, S. M. Humayun;Dong, Hoai-Bac;Yoon, Gi-Wan
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2007년도 추계종합학술대회
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    • pp.196-199
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    • 2007
  • In this paper, we studied a ZnO-based film bulk acoustic wave resonator (FBAR) device fabricated on top of a novel multi-layered Bragg reflector with chromium adhesion layers $(0.03{\mu}m-thick)$ inserted. The performance of FBAR device could be significantly improved using proper thermal treatments. At ${\sim}2.75$ GHz, we could achieve good return loss and quality factor (Q). This device fabrication technique will be useful for the future mobile WiMAX applications.

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High Performance On-Chip Integrable Inductor for RF Applications

  • Lee, J.Y.;Kim, J.H.;Kim, M.J.;Moon, S.S.;Kim, I.H.;Lee, Y.H.;Yook, Jong-Gwan;Kukjin Chun
    • 반도체디스플레이기술학회지
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    • 제2권1호
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    • pp.11-14
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    • 2003
  • The high Q(quality factor) suspended spiral inductors were fabricated on the silicon substrate by 3D surface micromachined process. The integration of 2.4GHz VCO has been performed by fabricating suspended spiral inductor of the top of CMOS VCO circuit. The phase noise of VCO integrated MEMS inductor is 93.5 dBc/Hz at 100kHz of offset frequency.

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Microstructural and Piezoelectric Characteristics of PSN-PMN-PZT Ceramics Produced by Attrition Milling

  • Juhyun Yoo;Sukkyu Min;Jaeil Hong;Sungjae Suh;R, Soonchul-U
    • Transactions on Electrical and Electronic Materials
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    • 제2권3호
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    • pp.18-23
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    • 2001
  • For the piezoelectric transformer application, Pb(Sb$\_$1/2/ Nb$\_$1/2/)O$_3$-Pb(Zr,Ti)O$_3$ ceramics were produced by attrition milling. Microstructural, dielectric and piezoelectric characteristics of the ceramics were investigated as a function of milling time. The particle size and grain size decreased while dielectric constant, density and mechanical quality factor (Q$\_$m/) increased with milling time. Temperature coefficient of resonant frequency (TCf$\_$r/) was shifted to positive side with increasing milling time. The attrition milling process proved to be one of the effective routes to produce transformers for high power application.

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Design and Fabrication of a Vacuum Chamber for a Commercial Atomic Force Microscope

  • Park, Sang-Joon;Jeong, Yeon-Uk;Park, Soyeun;Lee, Yong Joong
    • Applied Science and Convergence Technology
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    • 제23권2호
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    • pp.97-102
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    • 2014
  • A vacuum chamber for a commercial atomic force microscope (AFM) is designed and fabricated. Only minimal modifications were made to an existing microscope in an effort to work in a vacuum environment, while most of the available AFM functionalities were kept intact. The optical alignment needed for proper AFM operations including a SLD (superluminescent diode) and a photodiode can be made externally without breaking the vacuum. A vacuum level of $5{\times}10^{-3}$ torr was achieved with a mechanical pump. An enhancement of the quality factor was observed along with a shift in the resonance frequency of a non-contact-mode cantilever in a vacuum. Topographical data of a calibration sample were also obtained in air and in a low vacuum using the non-contact mode and the results were compared.

Bragg 반사층을 이용한 IMT-2000 대역통과필터용 체적 탄성파 공진기 (Film Bulk Acoustic Resonator(FBAR) using Bragg Reflector for IMT-2000 Bandpass Filter)

  • 김상희;김종헌;박희대;이시형;이전국
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 하계학술대회 논문집
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    • pp.377-382
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    • 2000
  • Film bulk acoustic resonator (FBAR) using AIN reactively sputtered at room temperature was fabricated. The FBAR is composed of a piezoelectric aluminium nitride thin film, top electrode of Al and bottom electrode of Au connected by a short (200${\mu}{\textrm}{m}$) transmission line on both sides and reflector layers of SiO$_2$- W Pair. The active areas of Al and Au were patterned using 150${\mu}{\textrm}{m}$ diameter shadow mask. The series resonance frequency (fs) and the parallel resonance frequency (fp) were measured at 1.976 GHz and 2.005 GHz, respectively. The minimum insertion loss and return loss were 6.1 dB and 37.19 dB, and the quality factor (Q) was 4261.

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한국 신용카드기업의 역량과 차별성 : 신용카드기업 종사자에 대한 Q 분석결과를 중심으로 (The Core Capabilities and Differences of Korean Credit Card Companies: Based on Q Analysis Results of Employers in Credit Card Companies)

  • 고형면
    • 한국조사연구학회지:조사연구
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    • 제9권2호
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    • pp.85-118
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    • 2008
  • 이 연구는 한국의 신용카드기얼 종사자들에게 Q 방법을 접목시켜, 해당 기업의 역량과 차별성을 검증하려는 목적 하에 이루어졌다. 사회과학 내에서 제도의 진화에 초점을 두는 이론 진영은, 기업 구성원들의 가장 일상적인 활동 속에 기업의 경쟁력이 배태돼(embedded) 있음을 강조한다. 즉 암묵적이면서도 비공식화된 방식으로 이루어지는 매일의 학습, 의사소통, 의사결정이 조직의 동태적 역량(dynamic capabilities)을 결정짓는다. 기업 구성원들의 내적, 잠재적 활동을 객관적으로 측정하고자 이 연구는, 계량화가 어려운 인간의 질적.주관적 속성들을 수치화시키는데 장점을 지닌 Q 방법을 활용한다. 분석결과에 의하면, 다수의 응답자들이 기업역량과 경쟁력의 질적 수준이 향상되어야 함을 강조한다. 하지만 응답자들 중 은행계의 경우 주로 성장 지향적 정책과 기업발전을 중시하며, 기업계는 정책으로부터의 독립성을 강조하나 기업조직 우선적 사고에 갇혀 있다. 2000년 이후 고착화된 한국 신용카드산업의 주기적인 부침은, 신용카드기업의 역량(경쟁력), 산업환경, 정책의 개선에 대한 기업현장의 기대나 요구가 충분히 반영되지 않은 것과 결코 무관하지 않다.

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Reliability and Validity of the Korean Version of the Cancer Stigma Scale

  • So, Hyang Sook;Chae, Myeong Jeong;Kim, Hye Young
    • 대한간호학회지
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    • 제47권1호
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    • pp.121-132
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    • 2017
  • Purpose: In this study the reliability and validity of the Korean version of the Cancer Stigma Scale (KCSS) was evaluated. Methods: The KCSS was formed through translation and modification of Cataldo Lung Cancer Stigma Scale. The KCSS, Psychological Symptom Inventory (PSI), and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire - Core 30 (EORTC QLQ-C30) were administered to 247 men and women diagnosed with one of the five major cancers. Construct validity, item convergent and discriminant validity, concurrent validity, known-group validity, and internal consistency reliability of the KCSS were evaluated. Results: Exploratory factor analysis supported the construct validity with a six-factor solution; that explained 65.7% of the total variance. The six-factor model was validated by confirmatory factor analysis (Q (${\chi}^2/df$)= 2.28, GFI=.84, AGFI=.81, NFI=.80, TLI=.86, RMR=.03, and RMSEA=.07). Concurrent validity was demonstrated with the QLQ-C30 (global: r=-.44; functional: r=-.19; symptom: r=.42). The KCSS had known-group validity. Cronbach's alpha coefficient for the 24 items was .89. Conclusion: The results of this study suggest that the 24-item KCSS has relatively acceptable reliability and validity and can be used in clinical research to assess cancer stigma and its impacts on health-related quality of life in Korean cancer patients.

PSN-PMN-PZT 세라믹스의 Zr/Ti 비에 따른 전기적 특성과 공진주파수의 온도안정성 (Electrical Properties and Temperature Stability of resonant Frequency with Zr/Ti ratio in PSN-PMN-PZT Ceramics)

  • 류주현;윤광희;민석규;이명수;서성재
    • 한국전기전자재료학회논문지
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    • 제13권8호
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    • pp.675-680
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    • 2000
  • In this study the temperature coefficient of resonant frequency(TC $F_{r}$) dielectric and piezoelectric properties of Pb[(S $b_{1}$2//N $b_{1}$2/)$_{0.065}$)-(Z $r_{x}$, $Ti_{1-x}$ )$_{0.90}$] $O_3$ceramics were investigated with Zr/Ti ratio. The compositions near the morphotropic phase boundary (MPB) appeared when Zr/Ti ratio was 49.5/50.5 The dielectric constant and electromechanical coupling factor( $k_{p}$) also showed the highest values of 1,257, 0.653 respectively when the Zr/Ti ratio was 49.5/50.5 Moreover the mechanical quality factor( $Q_{m}$) showed th lowest value of 713 when the Zr/Ti ratio. The temperature coefficient of resonant frequency(TC $F_{r}$) abruptly change at the morphotropic phase boundary(MPB) which existed between the rhombohedral phase with highly negative TC $F_{r}$ of -106ppm/$^{\circ}C$ and the tetragonal phase with highly positive TC $F_{r}$ of +64pp $m^{\circ}C$ as Zr/Ti ratio varied from 50/50 to 49.5/50.5.50.5..50.5.

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