• Title/Summary/Keyword: Physical optics

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Fresnel Zone Plate Antenna Analysis using PO Method (PO법을 이용한 프레넬 존 플레이트 안테나 해석)

  • Kim, Tae-Yong;Lee, Hoon-Jae
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2012.05a
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    • pp.74-76
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    • 2012
  • In order to design Transceiver/Receiver antenna with high gain in Ka band, Fresnel zone plate lend(FZPL) antenna is considered and analyzed. Physical optics is applied to demonstrate the FZPL. The FZPL is configured to 11 elements diffraction zones and drived at 20GHz. As a result, calculated received gain using PO method is 33.01dB.

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Evaluation of Physical Properties of Polymeric Material Containing Vinyl-Substituted Naphthalene and Anthracene for Ophthalmic Application (안의료용 렌즈 적용을 위한 Vinyl Group으로 치환된 Naphthalene 및 Anthracene을 포함하는 고분자 소재의 물성평가)

Athermal Elastomeric Lens Mount for Space Optics

  • Kihm, Hag-Yong;Yang, Ho-Soon;Moon, Il-Kweon;Lee, Yun-Woo
    • Journal of the Optical Society of Korea
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    • v.13 no.2
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    • pp.201-205
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    • 2009
  • We investigated the optimum adhesive thickness for athermalizing an elastomeric lens mount in our space optics application. Theoretical results were compared with finite element solutions using two different models; discrete circular pads and discrete circular pads with columns filling the insertion holes reflecting the reality. A noticeable difference between their optimal thicknesses was observed, and physical interpretation revealed the uncertainty of prevailing athermal equations. A pilot sample was made to check our results and thermo-optical stress was assessed using an interferometer after isothermal load. This study presented insight into preliminary design guidance in elastomeric lens mounting.

The Impact of Refractive Errors on Quality of Life in Elementary School Children (초등학교 학생의 근시도가 삶의 질에 미치는 영향)

  • Kim, Hyojin;Kim, Eun-Ji;Kim, Jong-Eun;Lee, Kyu-Byung;Lee, Eun-Hee;Park, Sang-Shin;Park, Jee-Hyun;Lee, Se-Eun
    • Journal of Korean Ophthalmic Optics Society
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    • v.15 no.2
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    • pp.175-183
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    • 2010
  • Purpose: This study investigated the impact of ametropia and myopia on health-related quality of life (QoL) measures in elementary schoolers. Methods: Elementary school children of 92 aged 12 to 13 were divided into emmetropia and myopia groups by spherical equivalent. Then myopia was classified into the low, moderate and high myopia groups. Vision-related QoL scores were determined using PedsQL 4.0 (Pediatric Quality of Life Inventory) with physical health (8 items), emotional functioning (4 items), social functioning (5 items) and school functioning (5 items). Results: The total QoL score in the myopia group appeared lower than that in the emmetropia group, however the difference was not statistically significant (p>0.05). When it comes to physical health (running or exercising) and social functioning (getting along with friends or being teased)-related questions, the QoL score in myopia was low compared with the emmetropia group (p<0.05). High myopia showed a low score in physical health items but there was no significant difference in overall QoL scores in comparison with other groups (p<0.05). Conclusions: Refractive errors does not have a great impact on the total health-related QoL in elementary school children but it causes discomfort in physical health and social functioning.

Analysis of Radar Cross Section of a Battleship Equipped with an Integrated Mast Module Based on PO and PTD

  • Shin, Hokeun;Lee, Seokgon;Park, Dongmin;Shin, Jinwoo;Chung, Myungsoo;Park, Sanghyun;Park, Yong Bae
    • Journal of electromagnetic engineering and science
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    • v.17 no.4
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    • pp.238-240
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    • 2017
  • In this paper, we analyze the radar cross section (RCS) of a battleship equipped with an integrated mast module (IMM). The RCS of a battleship equipped with an IMM is calculated based on physical optics (PO) and the physical theory of diffraction (PTD), and is analyzed in terms of the mast shape, incident angles, and polarization.

High-frequency Back-scattering Cross Section Analysis of Rotating Targets (회전 표적의 고주파수 후방산란단면적 해석)

  • Kim, Kook-Hyun;Cho, Dae-Seung;Kim, Jin-Hyeong
    • Journal of the Korea Institute of Military Science and Technology
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    • v.10 no.3
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    • pp.16-24
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    • 2007
  • The high-frequency analysis method of back-scattering cross section spectrum of rotating targets is established. The time history of the back-scattering cross section is calculated using a quasi-stationary approach, based on a physical optics and a physical theory of diffraction, combining an adaptive triangular beam method to consider the shadow effect. And the spectra of back-scattering cross section by the Doppler effect are analyzed applying a simple fast Fourier transform method to its time history. The numerical calculation for rotating targets, such as rotating metal plates and underwater propeller, are carried out. The time history appears to be periodic with respect to the number of wings. The backscattering cross section spectrum level and its frequency shift are dependent on the rotating speed, direction, and the shape of the targets.