• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.408-409
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• 2007

Ferrule function have connect Optical Communication Cable. But Ferrule have important role that is decided transmission efficiency and information quality. Key-point of detailed drawing of ferrule is Anti-Reflection. In the study Broadband Anti-Reflection coating Film was design for ferrule of optical connector and deposited in low temperature by Ion-Assisted Deposition system. Optical thin film materials($Ta_2O_5$, $SiO_2$) were manufactured Index and Film thickness. $Ta_2O_5$ index is 2.123 ~ 2.125 and $SiO_2$ is 1.44 ~ 1.442. Reflection Loss of film deposited on Ferrule is 30.1[dB].

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04c
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• pp.80-81
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• 2008

In this paper, we have designed the Anti-Reflection (AR) coating for 850, 1310 nm(multi type) and 1310, 1550 nm(multi type) wavelength ranges on the ferrule facet of special optical connector. The reflectance of the AR coated ferrule facet is designed under 5% for 850, 1310 nm(multi type) and 1310, 1550 nm (multi type). The average return loss of the AR coated ferrule facet is 47.1 dB.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.450-451
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• 2008

In this paper, we have designed the Anti-Reflection (AR) coating for 850, 1310 nm(multi type) and 1310, 1550 nm(multi type) wavelength ranges on the ferrule facet of special optical connector. The reflectance of the AR coated ferrule facet is designed under 5% for 850, 1310 nm(multi type) and 1310, 1550 nm (multi type). AR thin film was deposited by ion- assisted deposition in low temperature. The average return loss of the AR coated ferrule facet is 47.1 dB.

• Journal of Advanced Research in Ocean Engineering
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• v.1 no.1
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• pp.44-54
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• 2015

Breakwaters are the coastal structures constructed either perpendicular (shore connected) or parallel (detached) to the coast. The main function of breakwater is to create a tranquil medium on its leeside by reflecting the waves and also dissipating the wave energy arriving from seaside, resulting in ease of manoeuvrability to boats or ships to their berthing places. Different types of breakwaters are being used at present, such as rubble mound breakwater, vertical wall type breakwater and composite breakwater. The objective of this paper is to investigate reflection coefficients (Kr) and dissipation (loss) coefficients (Kl) for physical models of Quarter circle caisson breakwater of three different radii of 0.550 m, 0.575 m and 0.600 m with S/D ratio of 2.5 (S=spacing between perforations, D=diameter of perforations). The models were tested in the monochromatic wave flume of the department, for different incident wave heights (Hi), Wave periods (T) and water depths (d). It was observed that reflection coefficient increased with increase in the wave steepness (Hi/gT2) and decreased with increase in depth parameter (d/gT2) and hs/d (Height of structure including rubble base/depth of water). The loss coefficient decreased with increase in the wave steepness and increased with increase in depth parameter and hs/d.

• Korean Journal of Computational Design and Engineering
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• v.2 no.3
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• pp.133-141
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• 1997

In the process of car body design, various surfaces are generated from the given boundary curves. Depending upon the method of the surface generation and the quality of the boundary curves provided, the resulting surfaces may have global or local irregularities in many cases. Thus it would be necessary for the designer to evaluate the surface quality and to modify the surface or to use the different generation method based on the evaluation results. This capability is very important because the defect of the surface quality detected in the production stage will require the rework of the dies and will cause a big loss in cost and time. A method of surface interrogation using reflection line is introduced. In this paper, We applied reflection mapping to generate reflection lines on the trimmed NURBS surface. Since reflection lines are obtained from reflection mapping that uses simple and physically acceptable mapping algorithm, they can be efficiently used to simulate the reflection test on the real part in the production line.

• The Journal of the Acoustical Society of Korea
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• v.22 no.8
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• pp.652-659
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• 2003

High-frequency(40∼120 kHz) reflection loss measurements on the water-sandy sediment with a flat interface were conducted in a water tank for various grazing angles. The water tank(5×5×5 m) was filled with a 0.5 m-thick-flat bottom of 0.5ø-mean-grain-size sand. Reflection losses, which were experimentally obtained as a function of grazing angle and frequency, were compared with the forward loss model, APL-UW model (Mourad & Jackson, 1989). For frequencies below 60 kHz, the observed losses well agree with the reflection loss model, however, in cases for frequencies above 70 kHz, the observed losses are greater by 2∼3 dB than the model results. The model calculation, which does not fully account for the vertical scale of roughness due to grain size, produce less bottom losses compared to the observations that correspond to large roughness based on the Rayleigh parameter in the wave scattering theory. In conclusion, for the same grain-size-sediment, as frequencies increase, the grainsize becomes the scale of roughness that could be very large for the frequencies above 70 kHz. Therefore, although the sea bottom was flat, we have to consider the frequency dependence of an effect of roughness within confidential interval of grain size distribution in reflection loss model.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.1 s.173
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• pp.173-181
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• 2000

Depending upon the method of the surface generation and the quality of the boundary curves provided, the resulting surfaces may have global or local irregularities in many cases. Thus it would be necessary for the designer to evaluate the surface quality and to modify the surface. This capability is very important because the defect of the surface requires the rework of the dies that causes a big loss in cost and delivery time. To simulate the reflection line test in the actual production line, a faster generation algorithm is presented. Among., various surface interrogation methods using reflection lines, Blinn-Newell type of reflection mapping is applied to generate reflection lines on the trimmed NURBS surface. The generation of reflection lines is formulated as a surface-plane intersection problem, and solved by surface-contouring techniques. In addition, a modified reflection map is proposed to eliminate the discontinuity of reflection lines due to the configuration of the reflection map. A fast reflection line algorithm is developed utilizing an efficient traced contouring technique, and proved to be well suited for real-time quality-assessment task.

• Current Optics and Photonics
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• v.4 no.6
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• pp.551-557
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• 2020

A mirror-in-slab waveguide is fabricated on a slab waveguide by using the refractive-index contrast between two materials, with the reflection performance depending on the slab waveguide's design. In this research, a slab waveguide design consisting of silicon (Si) as the core and SiO2 as the substrate was designed and developed to determine the coupling, waveguide, and mirror losses. Based on experimental results, coupling loss is dominant and is affected by the design of the slab waveguide. Furthermore, the mirror loss is affected by the design of the mirror, such as the curvature radius and the size of the mirror. TE and TM polarizations of light are used in the measurements. The experimental results show that mirror losses due to reflection by mirrors are 0.011 dB/mirror and 0.007 dB/mirror for TE and TM polarizations respectively. A simulation was performed to confirm whether the size of mirror is sufficient to reflect the input light, and to check the quality of the surfaces of fabricated mirrors.

• Journal of the Semiconductor & Display Technology
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• v.23 no.1
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• pp.97-103
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• 2024

In this paper, the difference between the S-parameter and the characteristic impedance according to the structural change of the fine pitch coaxial socket was analyzed. A pitch of the probe pin was applied to 0.20mm, and ground pins of different conditions were placed on each of the five signal pins. Insertion loss and reflection loss were analyzed for the coaxial socket of normal structure and the two sockets of the proposed structure. In addition, the difference in characteristic impedance was analyzed using time domain reflectometry. Through the analysis, it was confirmed that the characteristic impedance was improved applying the new structures of the socket at the same pitch

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.55-63
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• 2018

In this paper, we measured the propagation path loss by a ground to air flight communication test at UHF band and analyzed the results. The ground receiving terminal was located at 1,100m above sea level in Cheju Island and the airborne transmit terminal flew at an altitude of 3.5km from 150 to 220km from the ground terminal. In this case, the ground terminal and the airborne terminal are on the Line of Sight. Therefore loss in this communications environment can be predicted based on Free Space Loss. However, in this test, the sea level exists between two terminals, and due to the very small angle of incidence on the reflecting surface due to the long-range communication environment, it is not possible to accurately predict the loss of free space only. Therefore, considering that there are no surrounding obstacles and that a line of sight is secured between the end of two terminals, we applied a plane earth reflection model and a spherical earth reflection model to estimate the propagation path loss and compared with the actual test results. As a result of the comparison, the predicted propagation path loss by a spherical earth reflection model were quite similar to the actual test values.