• Title/Summary/Keyword: Huygens' Principle

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A Geometrical Analysis Method of ELC Lens for The 3D Display for Optimum Design (3차원 영상출력을 위한 ELC 렌즈의 기하광학적 해석 방법 및 최적 설계)

  • Kim, Bong-Sik;Kim, Keon-Woo;Baik, Seung-Jo;Park, Woo-Sang
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.6
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    • pp.457-461
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    • 2013
  • In this paper, a novel method based on geometrical optics is proposed to calculate the optical characteristics of an electric field driven liquid crystal (ELC) lens. For an optimally designed ELC lens, effective refractive index is calculated and then ray tracing is carried out using Huygens' principle. From the results, the intensity distribution at the optimum viewing distance (OVD) is obtained. To confirm the validity of our work, the result is compared with that calculated by the extended Jones matrix method (EJMM). As a result, it turns out that the novel method provides more simple and rigorous simulation results than the EJMM.

The study on piezoelectric transducers: theoretical analysis and experimental verification

  • Sung, Chia-Chung;Tien, Szu-Chi
    • Smart Structures and Systems
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    • v.15 no.4
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    • pp.1063-1083
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    • 2015
  • The main purpose of this research is to utilize simple mathematical models to depict the vibration behavior and the resulted sound field of a piezoelectric disk for ultrasonic transducers. Instead of using 1-D vibration model, coupled effect between the thickness and the radial motions was considered to be close to the real vibration behavior. Moreover, Huygens-Fresnel principle was used in both incident and reflected waves to analyze the sound field under obstacles in finite distance. Results of the tested piezoelectric disk show that, discrepancies between the simulation and experiment are 2.5% for resonant frequency and 12% for resulted sound field. Therefore, the proposed method can be used to reduce the complexity in modeling vibration problems, and increase the reliability on analyzing piezoeletric transducers in the design stage.

Fresnel Diffraction and Fraunhoffer Diffraction (TEM 관련 이론해설 (1): 프레넬 회절과 프라운호퍼 회절)

  • Lee, Hwack-Joo
    • Applied Microscopy
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    • v.32 no.2
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    • pp.81-90
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    • 2002
  • In this review, the author discussed how the Fresnel and Fraunhoffer Diffraction can be deduced from the Huygens-Fresnel principle and Kirchhoff Diffraction Theory. Fresnel diffraction became the basic theory of the CTEM image theory, and Fraunhoffer diffraction became the base for electron diffraction and HRTEM image theory by Fourier transformation. The author also discussed the diffraction based on Born series.

Prediction of Antenna Propagation Characteristic in Space Environment Using Ray Tracing Method (광선 추적법을 이용한 우주 환경에서의 안테나 전파 특성 예측)

  • Kim, ChangSeong;Park, Yong Bae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.11
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    • pp.1023-1026
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    • 2016
  • We calculate the propagation characteristic of antennas considering refractive indices of space environments. The effective indices of troposphere, stratosphere, and inonshpere are computed and the ray tracing method, geometrical optics, and Huygens' principle are used to estimate refracted and attenuated electromagnetic wave of space environment.

An Optical Asynchronous Transfer Mode(ATM) Switching System Using Free Space Optics and an Output Buffer Memory (자유공간 광학과 출력 버퍼 메모리를 이용한 광 Asynchronous Transfer Mode(ATM) 교환방식)

  • 지윤규;이상신
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.16 no.4
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    • pp.326-334
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    • 1991
  • We propose an optical Asynchronous Transfer Mode(ATM) switching system using free-space optics and an output buffer memory. The distributor system in the switching fabric was analyzed using the Huygens-Fresnel principle and lens transformation. For monochromatic illumination, a pattern similar to the Fourier transform of the input distribution was observed across the output plane. A spatially broadened intensity distribution across the the output plane can be expected when the system is illminated with a partially coherent, quasimonochromatic beam. Spatially coherent pulses as short as 100fs can propagate through the distributor without severe spatial broadening.

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Effect of the covariance function on the statistics of speckle propagation through the turbulent atmosphere. (교란 대기를 통한 스펙클 전파의 통계적 코바리언스 함수의 효과)

  • 성평식;박계원
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.3 no.1
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    • pp.29-34
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    • 1999
  • In the paper, the extened Huygens-Fresnel principle has been used to make an analysis of the statistics the received intensity for speckle propagation though the turbulent atmosphere. The results of these formulations include of the log-amplitude covariance as well as the wave structure functions, and It was found that the normalized variance is dependent on the turblence strength and rises above unity.

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Squint-less Phased Array Antenna Near-field Subwavelength Focusing with True-time Optical Delay Line (광 지연선로를 이용한 스퀸팅이 없는 위상배열 안테나의 근접장 서브파장 포커싱)

  • Jung, Young Jin
    • Korean Journal of Optics and Photonics
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    • v.30 no.3
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    • pp.94-100
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    • 2019
  • The near-field subwavelength squint-less focusing system of a phased array antenna is designed and demonstrated by numerical simulation. The Huygens-Fresnel principle is applied to numerical simulation for calculation of the phased array antenna at microwave frequency. It was shown that beam squinting can be eliminated, utilizing true-time optical delay lines based on a chirped fiber grating in the proposed system. Furthermore, subwavelength focusing with high numerical aperture can be achieved by considering the fact that the array elements of the phased-array antenna can be treated as diffractive elements in an optical lens system. Also, side lobes can be suppressed by decreasing the distance between element antennas to less than half of the wavelength.

Influence of Detailed Structure and Curvature of Woven Fabric on the Luminescence Effect of Wearable Optical Fiber Fabric (직물의 세부 구조 및 굴곡이 웨어러블 광섬유의 발광 효과에 미치는 영향)

  • Yang, Jin-Hee;Cho, Hyun-Seung;Kwak, Hwy-Kuen;Oh, Yun-Jung;Lee, Joo-Hyeon
    • Science of Emotion and Sensibility
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    • v.21 no.4
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    • pp.55-62
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    • 2018
  • The two main requirements of wearable optical fiber fabrics are that they must presuppose a high degree of flexibility and they must maintain the luminance effect in both flat and bent conformations. Therefore, woven optical fiber fabrics that satisfy the above conditions were developed by both weaving and by using computer embroidery. First, we measured the brightness of the wearable optical fiber fabric in the flat state at a total of 10 measurement points at intervals of 1 cm. Second, the wearable optical fiber fabric was placed horizontally on the forearm, where three-dimensional bending occurs, and the luminance values were recorded at the same 10 measurement points. For the woven fabric in the flat state, the maximum, minimum, average, and standard deviation luminance values were $5.23cd/m^2$, $2.74cd/m^2$, $3.56cd/m^2$, and $1.11cd/m^2$, respectively. The corresponding luminance values from the bent forearm were $7.92cd/m^2$ (maximum), $2.37cd/m^2$ (minimum), $4.42cd/m^2$ (average), and $2.16cd/m^2$ (standard deviation). In the case of the computer-embroidered fabric, the maximum, minimum, average, and standard deviation luminance values in the flat state were $7.56cd/m^2$, $3.84cd/m^2$, $5.13cd/m^2$, and $1.04cd/m^2$, respectively, and in the bent forearm state were $9.6cd/m^2$, $3.63cd/m^2$, $6.13cd/m^2$, and $2.26cd/m^2$, respectively. Therefore, the computer-embroidered fabric exhibited a higher luminous effect than the woven fabric because the detailed structure reduced light-loss due to the backside fabric. In both types of wearable optical fiber fabric the luminance at the forearm was 124% and 119%, respectively, and the light emitting effect of the optical fiber fabric was maintained even when bent by the human body. This is consistent with the principle of Huygens, which defines the wave theory of light, and also the Huygens-Fresnel-Kirchhoff principle, which states that the intensity of light increases according to the magnitude of the angle of propagation of the light wavefront (${\theta}$).

Polarization Properties of Quasi-Homogeneous Beams Propagating in Oceanic Turbulence

  • Chen, Feinan;Zhao, Qi;Chen, Yanru;Chen, Jingjing
    • Journal of the Optical Society of Korea
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    • v.17 no.2
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    • pp.130-135
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    • 2013
  • Based on the extended Huygens-Fresnel principle and generalized Stokes theory, the evolution of polarization properties of beams generated by quasi-homogenous (QH) sources propagating in clear oceanic water was studied by the use of the oceanic turbulence spatial spectrum function. The results show that the beams have similar polarization self-reconstructed behavior under different turbulence conditions in the far field, but if the propagation distance is not long enough, the degree of polarization (DOP) fluctuates with much more complexity than state of polarization (SOP) of QH beams. The self-reconstructed ability of DOP at the special distance in turbulence would get to the best value if the values of coherence of width were chosen suitably, but for SOP, it has no best value.

Radiation from a Millimeter-Wave Rectangular Waveguide Slot Array Antenna Enclosed by a Von Karman Radome

  • Kim, Jihyung;Song, Sung Chan;Shin, Hokeun;Park, Yong Bae
    • Journal of electromagnetic engineering and science
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    • v.18 no.3
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    • pp.154-159
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    • 2018
  • In this paper, electromagnetic radiation from a slot array antenna enclosed by a Von Karman radome is analyzed by using the ray tracing method and Huygens's principle. We consider the rectangular slot array antenna and the Von Karman radome. The radiation patterns are calculated by using the surface currents of the radome to illustrate the electromagnetic behaviors of the radome-enclosed waveguide slot array antenna.