• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.10
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• pp.1089-1095
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• 2003

In this paper, the 26 GHz band omnidirectional antenna that produces an isotropic radiation pattern in the azimuth plane and a directive radiation pattern in the elevation plane was designed by using reflector antennas. To investigate the reliability of the designed antenna, that was analyzed by using the aperture field method and the calculated value was compared with the measured value. An good agreement was achieved between the calculated characteristics and the experimental performance. We found that the designed antenna in this paper can be used as the omnidirectional antenna with reflectors and the analysis method in this paper can be used for the analysis of this type antenna.

• Journal of the Optical Society of Korea
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• v.14 no.1
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• pp.38-41
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• 2010

We design and fabricate a widely tunable laser diode made of InGaAsP-InP. The diode is monolithically integrated with a wavelength-selective coupled-ring reflector and semiconductor amplifiers. For realization of a compact size device, deeply etched multi-mode interference couplers and square ring resonators composed of total-internal-reflection mirrors are adopted and fabricated using a self-aligned process. It is demonstrated that the laser diode exhibits single mode operation and 16 nm tuning range with side-mode-suppression-ratio exceeding 20 dB.

• Proceedings of the Korean Nuclear Society Conference
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• 2003.05a
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• pp.65-65
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• 2003

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.1 no.1
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• pp.61-66
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• 1987

This paper deals with the Design of lamp reflector which can statisfy the required candlepower distribution. Until now the process of design is made by the help of the personal expenences and inspiration and also in case of the ready-made CAD algorithm the effects of the diffusive reflection in reflective surface are neglected and the CPU time is too long. To overcome these limits a new CAD algorithm is made. This new algorithm can provide an easy and swift design by which high efficiency and proper candlipower distribution are possible.

• Proceedings of KOSOMES biannual meeting
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• 2003.05a
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• pp.125-134
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• 2003

This paper describes on the design of Passive-type Radar Reflector for small Ship (PRR-S) based on the newly revised 2000 SOLAS regulations. The design idea, adopted in the study, is to hold PRR-S in the proper ‘catch rain’ position to avoid fluctuations of Radar Cross Section (RCS) due to ship's heeling. The PRR-S consists of octahedral-type radar reflector with circular plates and three-axis gimbaled stabilizer with weight on the bottom of outer gimbal ring. Performance test for the PRR is carried out in an anechoic chamber. The test results show that the reflected radar signal from PRR-S is more uniformly distributed than the reference model (Davis Echomaster).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.10
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• pp.1177-1183
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• 2010

In this paper, design of a microstrip-fed, Spidron fractal-shaped slot antenna with circular polarization is represented. The ground plane of the designed antenna has a slot that comprises seven right-angled triangle next to each other in a low. A reflector is placed at the bottom on microstrip feeding line to enhance the antenna gain. The optimized design was conducted by varying a length of the first right-angled triangle, location of feeding line, space between a substrate and a reflector. The proposed antenna was fabricated on a Taconic-RF35 substrate. The entire dimension of the fabricated antenna is $40{\times}40{\times}18.6mm^3$ and the reflector is 18.6 mm away from the ground plane. The measured gain of the fabricated antenna is 6.7 dBi at 4.3 GHz. The measured bandwidths of -10 dB reflection and 3 dB axial ratio are 41 % and 7.4 %, respectively.

• Korean Journal of Optics and Photonics
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• v.29 no.6
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• pp.253-261
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• 2018

In this paper, we study a method of designing a reflector for LED light sources with an asymmetric light distribution. In a sports game, lighting with a symmetric distribution makes the athlete and spectators look directly at the light source, so it can cause glare. We derive the optimal tilt angle and design a reflector with asymmetric light distribution to solve these problems. Afterward, performance is analyzed according to the tennis-court lighting standard, and is confirmed to meet the class 1 European standard.

• Journal of Digital Convergence
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• v.14 no.4
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• pp.419-424
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• 2016

In this paper, we studied a light distribution for the LED chips arrangement using an optical design software. The structures of the edge type LED luminaires are reflector plane, LGP(lighting guide plane) and diffuse plane. The reflector plane is on the middle of the overall structure. We had simulation that placing LED chips on the reflector center of the reflector edge by changing the position of LED chips above the reflector center at 1mm, 2mm, and 3mm respectively. In the case, when LED chips are on the center of the reflector, it shows the light distribution of the general diffuse illumination, the semi-direct distribution with 0.56 efficiency and the direct distribution with 0.31 efficiency. And the wedge type LGP shows more efficiency than the flat type. Gradually increasing shape of semi-spherical type by 0.015mm has power of 1.02W, efficiency of 0.25, and maximum luminous intensity of 0.104W/sr, it also and shows the better optical characteristics than the reflector plane that have no patterns. This semi-spherical type shows the better optical characteristics than the reflector plane that have no patterns.

• Nuclear Engineering and Technology
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• v.52 no.3
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• pp.633-646
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• 2020

Imaging and scattering techniques using thermal neutrons allow to analyze complex specimens in scientific and industrial researches. Owing to this advantage, there have been a considerable demand for neutron facilities in the industrial sector. Among neutron sources, an accelerator driven compact neutron source is the only one that can satisfy the various requirements-construction budget, facility size, and required neutron flux-of industrial applications. In this paper, a target, moderator, and reflector (TMR) system for low-energy proton-accelerator driven compact thermal neutron source was designed via Monte Carlo simulations. For 10-30 MeV proton beams, the optimal conditions of the beryllium target were determined by considering the neutron yield and the blistering of the target. For a non-borated polyethylene moderator, the neutronic properties were verified based on its thickness. For a reflector, three candidates-light water, beryllium, and graphite-were considered as reflector materials, and the optimal conditions were identified. The results verified that the neutronic intensity varied in the order beryllium > light water > graphite, the compacter size in the order light water < beryllium < graphite and the shorter emission time in the order graphite < light water < beryllium. The performance of the designed TMR system was compared with that of existing facilities and were laid between performance of existing facilities.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.6
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• pp.515-521
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• 2014

In this paper, we designed axis-displaced Gregorian antenna by using Ray-tracing method. This antenna improves gain, VSWR by rotating the axis of the sub-reflector to get rid of E-field wave returned from sub-reflector to feed horn. Therefore it reduce the sub-reflector size and the volume of antenna. This method is used to track the propagation path for radiation pattern of feed horn from feed horn to sub-reflector, main-reflector and air. We get E-field distribution of this antenna aperture and calculate antenna radiation pattern and optimize the antenna performance. The Ray-tracing Method was verified because the gain, radiation patterns, side lobe level, beam width and return loss of the designed antenna are very similar to CST simulation result and a measured result of the fabricated antenna.