• Title/Summary/Keyword: mmWave

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Development and Goals of smart EM wave absorber with heat radiating function

  • Choi, Dong Soo;Kim, Dong Il;Kim, Do Yeol;Choi, Dong Han
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2012.10a
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    • pp.125-127
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    • 2012
  • With the progress of electronics and radio communication technology, human enjoys greater freedom in communication. However, EMW (Electro-Magnetic wave) environments have became complicate and more difficult to control. Thus, international organizations, such as the American National Standard Institution (ANSI), Federal Communications Commission (FCC), the Comite Internationale Special des Perturbations Radio electrique (CISPR), etc, have provided standard for controlling the EM wave environments and for the countermeasure of the electromagnetic compatibility (EMC). In this paper, the status of EMW absorber and the goal of smart EMW absorber ifor the future were described. Furthermore, design method of the smart EM wave Absorber with heat radiating function was suggested. The designed smart EM wave Absorber has the absoption ability of more than 5 dB from 2 GHz to 2.45 GHz band, one optimum aperture (hole) size of which was 6 mm, 9 mm in adjacent hole space, and 6.5 mm in thickness, respectivly. Thus, it is repected that these results can be applied to various EMC devices in electronic, communication, and controlling systems.

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Development of Composite Sr Ferrite EM Wave Absorbers for GHz Frequency (GHz 대역용 복합형 Sr 페라이트 전파 흡수체의 개발)

  • Kim, Dong-Il;Moon, Sang-Hyun;Shin, Sung-Jae;Song, Jae-Man;Kim, Ki-Man
    • Journal of Navigation and Port Research
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    • v.28 no.6
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    • pp.503-507
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    • 2004
  • We prepared EM wave absorbers by using recycled Sr ferrite for GHz frequency, and investigated the effects of carbon additions and preparation temperatures on their EM wave absorption properties. A Sr ferrite EM wave absorber with the ratio of Sr ferrite: silicon rubber: carbon = 80 : 13.6: 6.4 wt% prepared at 7$0^{\circ}C$ showed -24 dB at 9.4 GHz and -23 dB at 5.5 GHz for 2 mm and 3 mm thickness, respectively.

Study on the Application of Microwave-heating System for Making Bent-wood Furniture(II) - Bending Processing Properties of Carpinus laxiflora BL. by Microwave-heating - (국산재(國産材) 곡목가구(曲木家具) 제조(製造)를 위한 Microwave-heating System 활용(活用)에 관한 연구(硏究)(II) - Microwave-heating에 의한 서어나무의 소재(素材) 휨가공특성 -)

  • So, Won-Tek
    • Journal of the Korean Wood Science and Technology
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    • v.25 no.2
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    • pp.52-60
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    • 1997
  • Hornbeam trees(Carpinus laxiflora BL.) are growing in Korea and have good characteristics such as relatively high density, fine texture, split- resistance, and white colour. However, they have seldom been used as manufacturing materials This study was carried out to evaluate the possibility of using hornbeam wood as bent, wood furniture materials. Softening methods were steaming and micro-wave heating. The specimens of $15{\times}15{\times}350mm$ were used green or air-dried, and were steamed at $100^{\circ}C$ for 20min, or microwave heat ed f or 60 seconds. The bending processing conditions are showed in Table 3. The minimum solid-bending radii of air-dried wood were 40mm for steaming and 200mm for micro-wave heating, respectively. And that of green wood were 40mm for micro-wave heating. In conclusion, both of the steamed wood and micro-wave heated green wood showed very good solid bending processing properties, but micro-wave heated air-dried wood were not sufficient for bent-wood furniture.

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Study on the Application of Microwave-heating System for Making Bent-wood Furniture(II) - Bending Processing Properties of Carpinus laxiflora BL. by Microwave-heating - (국산재(國産材) 곡목가구(曲木家具) 제조(製造)를 위한 Microwave-heating System 활용(活用)에 관한 연구(硏究)(II) - Microwave-heating에 의한 서어나무의 소재(素材) 휨가공특성 -)

  • So, Won-Tek
    • Journal of the Korean Wood Science and Technology
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    • v.11 no.2
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    • pp.52-60
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    • 1983
  • Hornbeam trees(Carpinus laxiflora BL.) are growing in Korea and have good characteristics such as relatively high density, fine texture, split-resistance, and white colour. However, they have seldom been used as manufacturing materials This study was carried out to evaluate the possibility of using hornbeam wood as bent-wood furniture materials. Softening methods were steaming and micro-wave heating. The specimens of $15{\times}15{\times}350mm$ were used green or air-dried, and were steamed at $100^{\circ}C$ for 20min, or microwave heated for 60 seconds. The bending processing conditions are showed in Table 3. The minimum solid-bending radii of air-dried wood were 40mm for steaming and 200mm for micro-wave heating, respectively. And that of green wood were 40mm for micro-wave heating. In conclusion, both of the steamed wood and micro-wave heated green wood showed very good solid bending processing properties, but micro-wave heated air-dried wood were not sufficient for bent-wood furniture.

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State-of-the-Art mmWave Antenna Packaging Methodologies

  • Hong, Wonbin
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.2
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    • pp.15-22
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    • 2013
  • Low-Temperature-cofired ceramics (LTCC) antenna packages have been extensively researched and utilized in recent years due to its excellent electrical properties and ease of implementing dense package integration topologies. This paper introduces some of the key research and development activities using LTCC packaging solutions for 60 GHz antennas at Samsung Electronics [1]. The LTCC 60 GHz antenna element topology is presented and its measured results are illustrated. However, despite its excellent performance, the high cost issues incurred with LTCC at millimeter wave (mmWave) frequencies for antenna packages remains one of the key impediments to mass market commercialization of mmWave antennas. To address this matter, for the first time to the author's best knowledge this paper alleviates the high cost of mmWave antenna packaging by devising a novel, broadband antenna package that is wholly based on low-cost, high volume FR4 Printed Circuit Board (PCB). The electrical properties of the FR4 substrate are first characterized to examine its feasibility at 60 GHz. Afterwards a compact multi-layer antenna package which exhibits more than 9 GHz measured bandwidth ($S_{11}{\leq}-10$ dB) from 57~66 GHz is devised. The measured normalized far-field radiation patterns and radiation efficiency are also presented and discussed.

A study on the visible wave of transmittance pressable ceramic core (열가압성형도재 코어의 가시광선 투과율에 관한 연구)

  • Jung, In-Ho;Lee, Sang-Deok;Nam, Sang-Yong
    • Journal of Technologic Dentistry
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    • v.34 no.1
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    • pp.1-9
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    • 2012
  • Purpose: The purpose of this study was to investigate the transmittance differences of pressable ceramic core due to thickness within the visible light spectrum. Methods: 36 specimens were divided into 2 groups (0.6mm, 0.8mm) which have each 3 specimens. The size of specimens was 10mm high and 10mm wide. The transmittance of specimens are measured by spectrophotometer Model Cary 500 that can measure infrared-ray, visible wave and ultraviolet-ray. Results: The results shows that there was no significant difference between specimen's thickness(0.6mm, 0.8mm) and transmittance. Conclusion: The individual's color perception is personal and there are numerous factors that influence on it. In general, human eye can perceive the color of thing only within visible light spectrum but in this experiment through spectrophotometer there was no big difference between specimen's thickness(0.6mm, 0.8mm) and transmittance. To sum up, The most important factors were a layed porcelain structure and its thickness rather than core thickness in the porcelain crown. Also, When making all ceramic core with dead pulp (nervous treatment tooth) when used as a restorative esthetic think is more efficient to improve.

Study Of Millimeter-Wave Passive Imaging Sensor Using the Horn Array Antenna (혼 배열 안테나를 이용한 밀리미터파 수동 이미징 센서 연구)

  • Lim, Hyun-Jun;Chae, Yeon-Sik;Kim, Mi-Ra;Rhee, Jin-Koo
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.47 no.2
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    • pp.74-79
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    • 2010
  • We have designed a millimeter-wave passive imaging sensor with multi-horn antenna array. Six horn array antenna is suggested that it is integrated into one housing, and this antenna is effectively configurated m space to assemble with LNA of WR-10 structure. Antenna is designed to have the peak gain of 17.5dBi at the center frequency of 94GHz, and the return loss of less than -25dB in W-band, and the small aperture size of $6mm{\times}9mm$ for antenna configuration with high resolution. LNA is designed to have total gain of more than 55dB and noise figure of less than 5dB for good sensitivity. We made a detector for DC output translation of millimeter-wave signal with zero bias Schottky diode. It is shown that good sensitivity of more than 500mV/mW.

The Effect of Glide Path on Canal Centering Ability in Reciprocating File System (Reciprocating 파일 시스템에서 Glide Path가 근관만곡도 유지에 미치는 영향)

  • Zang, Ki-Choul;Kim, Jin-Woo;Cho, Kyung-Mo;Park, Se-Hee
    • Journal of Dental Rehabilitation and Applied Science
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    • v.28 no.3
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    • pp.245-252
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    • 2012
  • The purpose of this study was to evaluate the influence of glide path on canal centering ratio after instrumentation with different single file systems; WaveOne and Reciproc. Reciproc R25 (VDW), WaveOne Primary (Dentsply Maillefer) and PathFile #13, 16, 19 (Dentsply Maillefer) were used in this study. In no glide path groups, Reciproc files and WaveOne files used for canal preparation without glide path. In glide path groups, the PathFile were used before canal preparation. Methylene blue dye was introduced into the canal to obtain a clear pre-instrumentation image. Pre-instrumentation images and post-instrumentation images were scanned using Epson Perfection V700 Photo scanner (Epson, Nagano, Japan). Transparencies of post-instrumentation images were changed and superimposed on pre-instrumentation images using Adobe Photoshop CS 3 (Adobe Systems Incorporated, San Jose, CA, USA). The centering ratio was calculated for each instrumented canal using the following formula: CR=|X1-X2|/Y. It was statistically analyzed using two-way ANOVA at 95% confidential level. The centering ratio in glide path groups were significant less than it in no glide path groups at 3, 4, 5 and 6 mm level. Except 1 and 6 mm level, WaveOne groups had significant less centering ration than Reciproc groups. At 6 mm level, there was no significant difference between WaveOne and Reciproc. In the limitation of this study, creation of a previous glide path before reciprocating motion instrumentation in curved canal appears to be appropriate and WaveOne system can be used for preparation of curved canal without severe aberrations.

A Study on FDTD Analysis and Fabrication of the Sheet-type Millimeter EM wave Absorber

  • Kim, Dae-Hun;Soo, Dong-Soo;Kim, Dong-Il
    • Journal of Navigation and Port Research
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    • v.34 no.4
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    • pp.299-304
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    • 2010
  • In this paper, the EM wave absorber was developed for the 94-GHz detecting radar system. To analysis an EM wave absorber in millimeter wave band, we fabricated three absorber samples using carbon black and titanium dioxide and permalloy with chlorinated polyethylene. After measuring the complex relative permittivity, the absorption characteristics are simulated by 1D FDTD according to different thicknesses of less than 1.0 mm. Then, the EM wave absorber was fabricated based on the FDTD simulation. As a result, the measured results agreed well with the simulated ones, and the developed EM wave absorber with a thickness of 0.7 mm had the desired absorption characteristics of more than 14 dB in the frequency range of the 94-GHz band.

Coverage Evaluation of mmWave Small Cell in Outdoor Environment (실외환경에서 밀리미터파 소형 셀의 커버리지 측정)

  • Nguyen, Thanh Ngoc;Jeon, Taehyun
    • Journal of Satellite, Information and Communications
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    • v.12 no.4
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    • pp.162-165
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    • 2017
  • In an effort to compensate the rising of the data throughput demand nowadays, there have been many research works to optimize the radio resource and increase the capacity of the network. At the present, small cell network, mmWave band and beamforming technology are leading the trend and becoming the core solutions of the fifth generation (5G) cellular networks. Since the propagation characteristics of radio wave in the mmWave band is quite different from the conventional bands, the communication systems which work in these bands have to be redesigned. In this paper, a 3D simulation model is discussed for cellular network at 60 GHz in outdoor environments. Coverage analysis and system performance is carried out for a small cell system in the typical urban environment including street canyon simulation scenario. In addition, the beamforming technique is considered to evaluate the throughput improvement. Simulation results show that the mmWave small cell systems is expected to be one of the major candidate technologies to satisfy the requirements of 5G in terms of data rate.