• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.543-546
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• 2001

So far, the design methods of quartz crystal resonator have been developed. Recently, as the electronic package and semiconductor modules become smaller, the need to minimize the sizes of crystal components grows larger. but Minimizing crystal plate sizes has limitations because its temperature-frequency characteristics is worse and unwanted resonances occur. so appropriate design of electrode size and crystal plates is necessary. In this palter, Two-dimensional governing equations for electroded piezoelectric crystal plates with general symmetry have been solved from deduced equations from three-dimensional equations of linear piezoelectricity in most cases. In practice, electroded piezoelectric crystal plates have three-dimensional geometry, so simplified 2-dimensional equations and 2-D modeling are insufficient for explaining its resonance modes and characteristics. So, three-dimensional FEM(finite element method) analysis is done and its effectiveness is verified from analyzing practical crystal resonator model.

• JSTS:Journal of Semiconductor Technology and Science
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• 제7권2호
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• pp.102-109
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• 2007

We propose and experimentally demonstrate a ring resonator with sharp U-turns fabricated on a silicon-on-insulator (SOI) substrate; the resonator was designed as a key part of an optical, dynamic data storage device. We discuss the optical properties of the fabricated ring resonator from the viewpoint of equi-frequency-contour behavior in a dispersion space. We successfully characterize its optical characteristics on the basis of photonic crystal physics. It is suggested that the photonic ring resonator will be applicable to optical, dynamic memory devices for optical communication systems.

• 전기학회논문지
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• 제60권4호
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• pp.817-822
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• 2011

We propose a novel ring structure based on the stadium-shaped ring resonator (SSRR) with dual photonic crystal microcavity (DPCM) for biosensor and analyzed the sensing characteristics. The Q-factor of the photonic crystal microcavity (PCM) can be significantly enhanced when the PCM or DPCM has the same resonance condition as the SSRR. The simulation results show that the Q-factor of the SRR with DPCM was increased by three times in comparison with single PCM structure. We also defined a mutual interference between two PCMs. Assuming a detectable spectral resolution of 10 picometers, a refractive index resolution of $3.03\times10-5$ can be measured on the SSRR-DPCM.

• 한국광학회:학술대회논문집
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• 한국광학회 2004년도 하계학술발표회
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• pp.154-155
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• 2004

• 한국전기전자재료학회논문지
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• 제18권7호
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• pp.610-614
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• 2005

In this paper, simple AT-cut crystal resonator utilizing $Bi_{0.5}(Na_{0.84}K_{0.16})_{0.5}TiO_3$ relaxator ceramics as load capacitator were designed and their frequency-temperature characteristics were investigated. In order to modify temperature dependance of dielectric constant, $Bi_{0.5}(Na_{0.84}K_{0.16})_{0.5}TiO_3$ ceramics were manufactured with the variations in Sr substitution. At the composition with $6\;mol\%$ Sr substitution as load capacitator, frequency-temperature characteristics of AT-cut crystal resonators with the series load capacitance were similarly varied as those of cut orientation variation, and also compensated.

• Journal of the Optical Society of Korea
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• 제2권1호
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• pp.1-4
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• 1998

The second harmonic light of an 842 nm diode laser was generated from a KNbO3 crystal in an external ring resonator. The power of the second harmonic light was about 0.8 mV at an input fundamental power of 87 mW. The laser frequency was stabilized to the resonance frequency of the ring resonator, and the frequency fluctuation was measured as about 3 MHz.

• Journal of the Optical Society of Korea
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• 제15권2호
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• pp.187-195
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• 2011

We have designed two photonic crystal waveguide (PCW) structures with output focused beams in order to achieve more coupling between photonic devices and decrease the mismatch losses in photonic integrated circuits. PCW with coupled resonator optical waveguide (CROW) termination has been optimized by both one dimensional (1D) and seven dimensional (7D) particle swarm optimization (PSO) algorithms by evaluating the fitness function by the finite difference time domain (FDTD) method. The 1D and 7D-optimizations caused the factors of 2.79 and 3.875 improvements in intensity of the main lobe compared to the non-optimized structure, whereas the FWHM in 7D-optimized structure was increased, unlike the 1D case. It has also been shown that the increment of focusing causes decrement of the bandwidth.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.135-138
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• 2003

The circular cavity resonator which can measure the dielectric properties of dielectrics in the V-band($50GHz{\sim}75GHz$) frequency range was designed and fabricated. Exciting and detecting of the resonator is peformed by WR15 rectangular waveguides using Bethe's small hole coupling. The GaAs plate sample was used for the verification of the performance of the fabricated circular cavity resonator. In the measurement of GaAs single crystal using that resonator, the resonant frequency of the dominant $TE_{011}$ mode, the permittivity and $Q{\times}f_0$ were measured as 53.29GHz, 12.87 and 138,000, respectively.

• 한국전산구조공학회논문집
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• 제27권2호
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• pp.63-70
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• 2014

본 논문에서는 압전 수정진동자의 설계민감도 해석 및 위상 최적설계 기법을 개발하였다. 압전 수정진동자는 가해지는 전하에 의해 두께방향 전단 변형하게 되거나, 혹은 그 반대방향으로 기계 변형에 의해 전기적 신호를 검출하게 된다. 엄밀한 두께방향 전단해석을 위해 두께방향으로 고차 보간을 하는 고차 민들린(Mindlin) 판 이론을 도입하였다. 압전 수정진동자에서 수정판은 부도체이기 때문에 전기적 신호를 검출하거나 전기적 신호에 의해 수정판을 기계적으로 진동시키기 위해 수정판의 상/하 표면에 얇은 전극경을 도포한다. 비록 전극경이 매우 얇기는 하지만 그 무게와 형상에 따라 진동자의 거동이 달라지기 때문에, 설계민감도 해석 및 위상 최적설계를 위한 설계변수는 전극경의 질량 밀도와 관계된다. 따라서 위상 최적설계 문제는 두께방향 전단 변형에너지를 최대화하는 최적의 전극경 분포를 구하도록 구성한다. 또한 보다 의미있는 설계안을 얻기 위해 전극경의 재료량과 면적에 제약조건을 부여한다. 두께방향 전단 주파수(고유치)와 상응하는 모드형상(고유벡터)에 대한 설계구배는 고유벡터 확장법을 이용한 해석적 설계민감도 해석법을 통해 매우 효율적이고 정확하게 계산될 수 있다. 수치예제를 통해 제안된 해석적 설계민감도가 유한차분 설계민감도와 비교하여 매우 효율적이고 정확하게 계산됨을 확인하였다. 또한 위상 최적설계를 통해 도출된 최적 전극경 설계가 모드형상과 두께방향 전단 변형에너지를 개선시킴을 확인하였다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 추계종합학술대회
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• pp.630-632
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• 2003

본 논문에서는 Ladder 형과 SCF 형의 구조를 가지는 FBAR 필터의 제작에 대해 발표한다. 단위공진기의 구조는 W/SiO$_2$, 반사층을 갖는 SMR (Solidly Mounted Resonate.) 구조을 가지며, 21,200$\mu$m$^2$의 공진 면적을 갖는 단위공진기의 $K^2$eff, Q$_{s}$ 그리고 Q$_{p}$는 각각 3.24%, 6,363 그리고 6,749의 값을 보였다. 이와같은 성능을 갖는 단위공진기를 기본으로 제작된 필터의 크기는 Ladder 형이 800$\times$2000($\mu\textrm{m}$$^2$)의 크기를 갖고 SCF 형이 600$\times$500($\mu\textrm{m}$$^2$)을 가진다. 먼저 필터의 기본이 되는 박막형 공진기를 최적화시키고, 이를 바탕으로 Ladder 형과 SCF형의 구조를 가지는 FBAR 필터를 제작하여 성능을 비교하였다.다..