• Title/Summary/Keyword: mutual radiation

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Wideband Characterization of Angled Double Bonding Wires for Microwave Devices (초고주파 소자를 위한 사잇각을 갖는 이중 본딩와이어의 광대역 특성 해석)

  • 윤상기;이해영
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.32A no.9
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    • pp.98-105
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    • 1995
  • Recent microwave IC's reach to the extent of high operating frequencies at which bonding wires limit their performance as dominant parasitic components. Double bonding wires separated by an internal angle have been firstly characterized using the Method of Moments with the incorporation of the ohmic resistance calculated by the phenomenological loss equivalence method. For a 30$^{\circ}$ internal angle, the calculated total reactance is 45% less than that of a single bonding wire due to the negative mutual coupling effect. The radiation effect has been observed decreasing the mutual inductance, whereas for parallel bonding wires it greatly increases the mutual inductance. This calculation results can be widely used for designing and packaging of high frequency and high density MMIC's and OEIC's.

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H-Plane Coupling Between Rectangular Microstrip antennas (구형 마이크로스트립 안테나의 H-Plane 상호결합)

  • Ko, Ji-Whan;Cho, Young-Ki;Son, Hyon
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.22 no.6
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    • pp.46-52
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    • 1985
  • A theoretical study of mutual coupling effects between two H-plane coupled microstrip patch antennas is presented. The radiation resistance and slot capacitance of a single micro-strip patch are calculated. To investigate the mutual coupling effects, the even and odd mode characteristic impedance and effective dielectric constants are obtained using the coupled microstrip line model. The S-parameter matrix elements 511,512 are used to study the mutual coupling e(facts in S-band frequency ranges for various patch spacings. Theoretical results and measurements are in good agreement.

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The Educational Pending Problems for the Safe Management of Diagnostic Imaging Equipment and the Current Status. (진단용 방사선 발생장치 안전관리를 위만 교육현안과 현주소)

  • Song Tea-ho;Gho Heung;Kim Myung-hoe
    • Journal of The Korean Radiological Technologist Association
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    • v.28 no.1
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    • pp.74-82
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    • 2002
  • 1. Purpose Presently, the service areas of those who we engaged in radiation works are being specialized. Thus, in this study, we propose a way for efficiently improving mutual relationship between the works of the radiation technicians(radiologists) and

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Radiation Characteristics of Patch Antennas with an Array of Pins for Various Substrate Thicknesses (기판 두께에 따른 핀 배열을 가지는 패치 안테나의 방사 특성)

  • Cho, Myung-Ki;Kim, Tae-Young;Kim, Boo-Gyoun
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.46 no.10
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    • pp.63-71
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    • 2009
  • The patch antennas with an array of pins with excellent radiation characteristics are investigated for several substrate thicknesses. The patch length of a pin array patch antenna for the maximum suppression of radiation in the horizontal plane decreases as the substrate thickness increases. The radiation in the horizontal plane of a pin array patch antenna is very small compared to that of a conventional patch antenna. The increase of forward radiation and the decrease of backward radiation of a pin array patch are obtained compared to those of a conventional patch antenna. The half-power beamwidth of E-plane radiation pattern of a pin array patch antenna is narrow compared to that of a conventional patch antenna so that the directivity is improved.

A study of registration algorithm based on 'Chamfer Matching' and 'Mutual Information Maximization' for anatomical image and nuclear medicine functional image ('Chamfer Matching'과 'Mutual Information Maximization' 알고리즘을 이용한 해부학적 영상과 핵의학 기능영상의 정합 연구)

  • Yang, Hee-Jong;Juh, Ra-hyeong;Song, Ju-Young;Suh, Tae-Suk
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2004.11a
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    • pp.104-107
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    • 2004
  • In this study, using brain phantom for multi-modality imaging, we acquired CT, MR and PET images and performed registration of these anatomical images and nuclear medicine functional images. The algorithms and program applied for registration were Chamfer Matching and Mutual Information Maximization algorithm which have been using frequently in clinic and verified accuracy respectively. In result, both algorithms were useful methods for CT-MR, CT-PET and MR-PET. But Mutual Information Maximization was more effective algorithm for low resolution image as nuclear medicine functional image.

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A LIMITED SURVEY OF DENTAL X-RAY UNITS AND PROTECTION IN KOREA (치과 X선발생장치 및 방어에 관한 조사연구)

  • Park T.W.
    • Journal of Korean Academy of Oral and Maxillofacial Radiology
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    • v.10 no.1
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    • pp.57-61
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    • 1980
  • In dental roentgenograph it is of mutual benefit to the patient and the dentist to use the minimum amount of radiation capable of producing roentgenograms with maximum interprtive informations. Recent increases in the number of diagnostic x-ray examinations made in this country have caused attention to be paid to the quantity of radiation delivered to the population and operator. The purposes of this study was to assess the quality of dental x-ray units, the amount of films, the average processing procedures and the radiation protection methods in korea. The results were as following: 1. Most of radiation generating system were used in low voltage such as 60Kvp, 10㎃. 2. High sensitivity films such as 'D' group of Kodak or Rinn were mainly used and average 14.7 films used per weeks. 3. Some dentists practiced visual processing technic in simple dark room, and others used instant films. 4. 68.26% of patient held the film themselves, but 27.30% were assisted by dentists film holding. 5. In radiation protection method, 7.85% of dentists had protection equipments such as protective barrier, 2.73% wore protective apron, 27.9% made it a rules to avoid beam, and 7.51% used to maintain a distance from the radiation source.

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A Study on the Image Registration Algorithms for the Accurate Application of Multimodality Image in Radiation Treatment Planning (방사선치료 계획시 다중영상 활용의 정확도 향상을 위한 영상정합 알고리즘 분석)

  • 송주영;이형구;최보영;윤세철;서태석
    • Progress in Medical Physics
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    • v.13 no.4
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    • pp.209-217
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    • 2002
  • There have been many studies on the application of the reciprocal advantages of multimodality image to define accurate target volume in the Process of radiation treatment planning. For the proper use of the multimodality images, the registration works between different modality images should be performed in advance. In this study, we selected chamfer matching method and mutual information method as most popular methods in recent image registration studies considering the registration accuracy and clinical practicality. And the two registration methods were analyzed to deduce the optimal registration method according to the characteristics of images. Lung phantom of which multimodality images could be acquired was fabricated and CT, MRI and SPECT images of the phantom were used in this study. We developed the registration program which can perform the two registration methods properly and analyzed the registration results which were produced by the developed program in many different images' conditions. Although the overall accuracy of the registration in both chamfer matching method and mutual information method was acceptable, the registration errors in SPECT images which had lower resolution and in degraded images of which data were removed in some part were increased when chamfer matching method was applied. Especially in the case of degraded reference image, chamfer matching methods produce relatively large errors compared with mutual information method. Mutual information method can be estimated as more robust registration method than chamfer matching method in this study because it did not need the prerequisite works, the extraction of accurate contour points, and it produced more accurate registration results consistently regardless of the images' characteristics. The analysis of the registration methods in this study can be expected to provide useful information to the utilization of multimodality images in delineating target volume for radiation treatment planning and in many other clinical applications.

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Design of Body RF Coil with Multiple Strips for Open MRI System by Pseudo Electric Dipole Radiation

  • 김경락;류승학;류연철;양형진;오창현
    • Proceedings of the KSMRM Conference
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    • 2002.11a
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    • pp.76-76
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    • 2002
  • Purpose: The purpose of this study is to optimize the configuration of body RF coil composed of 4 planar subcoils for low field open MRI. Method: Our low field RE coil is composed of 4 subcoils assumed to be located at both the bottom and top sides of permanent magnet. Each subcoils has 3 main strips. The coil system has mirror inversion symmetry. First, the currents on the strips are obtained by inductance calculation and circuit analysis, Second, all the strips are divided into line strip elements across the strips, the self Inductances of line strip elements and the mutual inductances among the line strip elements are calculated, and current distributions of strip are obtained by circuit analysis, where each strip is considered as parallel combination of line strip elements. Finally all the line strip elements are segmented, magnetic field has been calculated by pseudo electric dipole radiation method, where the current elements are regarded as pseudo electric dipole radiation sources. We have performed above procedures for various configurations of RE coil. The field homogeneity is calculated in the 25 cm DSV.

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Effect of Feed Substrate Thickness on the Bandwidth and Radiation Characteristics of an Aperture-Coupled Microstrip Antenna with a High Permittivity Feed Substrate

  • Kim, Jae-Hyun;Kim, Boo-Gyoun
    • Journal of electromagnetic engineering and science
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    • v.18 no.2
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    • pp.101-107
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    • 2018
  • The impedance bandwidth and radiation characteristics of an aperture-coupled microstrip line-fed patch antenna (ACMPA) with a high permittivity (${\varepsilon}_r=10$) feed substrate suitable for integration with a monolithic microwave integrated circuit (MMIC) are investigated for various feed substrate thicknesses through an experiment and computer simulation. The impedance bandwidth of an ACMPA with a high permittivity feed substrate increases as the feed substrate thickness decreases. Furthermore, the front-to-back ratio of an ACMPA with a high permittivity feed substrate increases and the cross-polarization level decreases as the feed substrate thickness decreases. As the impedance bandwidth of an ACMPA with a high permittivity feed substrate increases and its radiation characteristics improve as the feed substrate thickness decreases, the ACMPA configuration becomes suitable for integration with an MMIC.

Effect of Finite Substrate Size on the Radiation Characteristics of H-plane Linear Array Antennas (유한한 기판 크기가 H-평면 선형 배열 안테나의 방사 특성에 미치는 영향)

  • Yoon, Young-Min;Kim, Boo-Gyoun
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.5
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    • pp.39-49
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    • 2013
  • The effect of the finite substrate size on the radiation characteristics of H-plane linear microstrip array antennas is investigated. The radiation characteristics versus scan angle are systematically analyzed for 5-element H-plane linear array antennas with various substrate sizes and element spacings for the substrates with different dielectric constants. The distance between the antenna center and the substrate edge on the E-plane for the enhancement of the radiation characteristics of the array antenna is presented.