• Title/Summary/Keyword: coaxial waveguide

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A Coaxial Waveguide-based Spatial Combiner Using Finline-to-Microstrip Transitions (핀라인-마이크로스트립 변환을 이용한 동축선로 도파관 형태의 공간 결합기)

  • Kim, Bo-Ki;Lee, Su-Hyun;Kim, Hyoung-Jong;Shin, Suk-Woo;Kim, Sang-Hoon;Kim, Jae-Duk;Choi, Jin-Joo;Kim, Seon-Joo
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.10 no.5
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    • pp.79-86
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    • 2011
  • In this paper, a S-band coaxial waveguide-based spatial combiner is proposed. The proposed combiner consists of coaxial waveguide, impedance transformer, and finline-to-microstrip transformer. The coaxial waveguide is used as the host of the combining circuits for higher output power and better uniformity by equally distributing the input power to each element. The finline-to-microstrip transformer is designed by using antipodal antenna, and obtained low reflection coefficient by applying the small reflection theorem. The measurement results show the coaxial waveguide combiner has a maximum combining efficiency of 95%.

Radiation Characteristics of Finite Strip-Grating Loaded Dielectric-Coated Coaxial Waveguide with Finite Periodic Thick Slots

  • Kim, Joong-Pyo;Lee, Chang-Won
    • Journal of electromagnetic engineering and science
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    • v.1 no.2
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    • pp.161-165
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    • 2001
  • The radiation characteristics of leaky wave emanated from finite strip-grating loaded dielectric coated coaxial waveguide with finite periodic thick slots are investigated theoretically. The rigorous integral equations are derived for the proposed structure using the courier transform, mode expansion, and sine series expansion of the electric current on metallic strips, and the simultaneous linear equations are obtained. The effects of finite strip-grating loading on a dielectric-coated coaxial waveguide with finite periodic thick slots are examined in terms of radiation characteristics.

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Design of a Compact Coaxial Waveguide Feed Horn for Dual Band (이중 대역 소형 동축 도파관 급전 혼 설계)

  • Yun, Sohyeun;Uhm, Manseok;Yom, Inbok
    • Journal of Satellite, Information and Communications
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    • v.10 no.3
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    • pp.109-113
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    • 2015
  • This paper presents the study results on a dual band feed horn for the focused reflector. A coaxial waveguide structure is attractive to avoid blockage from the feeder. The inner conductor as a hollow waveguide is designed to excite TE11 of a circular waveguide for high frequency. For low frequency, the design of the outer coaxial waveguide that propagates coaxial TE11 and prevents fundamental TEM is presented. The horn size for generation of these modes results in the degradation of performance. The return loss is improved by a capacitive iris and an inductive iris The enhanced pattern symmetry by dual mode is presented. The horn design in this paper are verified through the test.

SAR Pattern of Biological Objects Contacted with Coaxial Waveguide Antenna Using the FDTD Method (유한 차분법을 이용한 동축 도파관 안테나에 접촉된 생체의 SAR 패턴에 관한 연구)

  • Koo, Sung-Mo;Lee, Chang-Won;Won, Chul-Ho;Cho, Jin-Ho
    • Journal of Biomedical Engineering Research
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    • v.18 no.3
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    • pp.261-266
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    • 1997
  • Nonevasive multifrequency microwave radiometry using coaxial waveguide antenna has been investigated for a homogeneous and four layer human body model. The coupling between coaxial waveguide antenna and a biological object was analyzed by use of the finite-difference time-domain(FDTD) method to obtain the absorbed power patterns in the media. The object studied in this paper was a homogeneous and four-layered lossy medium. The specific absorption rates(SAR) distribution which was corresponding to the temperature distribution was calculated in each region by use of the steady-state response in FDTD method. The SAR pattern of 1.2GHz was compared with that of 1.8GHz.

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SAR Pattern of Biological Objects Contacted with Coaxial Waveguide Using the FDTD Method

  • Koo, Sung-Mo;Won, Chul-Ho;Lee, Chang-Won;Cho, Jin-Ho
    • Proceedings of the KOSOMBE Conference
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    • v.1996 no.11
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    • pp.185-188
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    • 1996
  • Noninvasive multifrequency microwave radiometry using coaxial waveguide antenna has been investigated for a homogeneous and four layer human body model. The coupling between coaxial waveguide antenna and a. biological object is analyzed by use of the FDTD method to obtain the absorbed power patterns in the media. The object studied in this paper is a homogeneous and four-layered lossy medium. The specific absorption rates(SAR) distribution is calculated in each region by use of the steady-state response in FDTD method.

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The Comparison with SAR Patterns of Biological Objects Contacted with Coaxial Waveguide Antenna Using the FDTD Method

  • Koo, S.M.;Kwon, K.H.;Lee, C.W.;Won, C.H.;Kim, M.N.;Cho, J.H.
    • Proceedings of the KOSOMBE Conference
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    • v.1997 no.11
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    • pp.272-275
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    • 1997
  • Noninvasive multifrequency microwave radiometry using coaxial waveguide antenna has been investigated for a homogeneous and our layer human body model. We derived finite-difference time-domain(FDTD) algorithm and equation of MUR and generalized perfectly matched layer(GPML) absorbing boundary conditions(ABCs) in cylindrical coordination. The coupling between coaxial waveguide antenna and a biological object was analyzed by use of the FDTD method using MUR and GPML ABCs to obtain the absorbed power patterns in the media. The specific absorption rates(SAR) distribution which was corresponding to the temperature distribution was calculated in each region by use of the steady-state response in FDTD method. The SAR patterns of FDTD method using MUR ABCs was compared with those of FDTD method using GPML ABCs.

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Characteristic modes of a longitudinal slot in the outer conductro of coaxial waveguide for scattering : TE case (외부도체면에 축방향 슬롯이 있는 동축선로 도파관의 산란에 대한 특성모드의 해석 : TE의 경우)

  • 윤리호;조영기
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.32A no.7
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    • pp.23-29
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    • 1995
  • A characteristic mode theory for longitudinal slot of arbitrary width in the outer conductor of coaxial waveguide is applied for calculating the characteristic magnetic currents, the characteristic fields, radiation patterns, and the fields evershere(inside and outside the guide, and in the aperture region). Numerical results of the equivalent magnetic currents and the radiation patterns are compared with those obtained by use of the method of moments.

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Scattering of Coaxial Waveguide with Periodic Axial Slots Using Characteristic Mode Theory : TE Case (특성모드 이론을 이용한 주기적인 축방향 슬롯이 있는 동축선로 도파관 구조의 산란특성 : TE의 경우)

  • 윤리호;조영기
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.8 no.6
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    • pp.629-635
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    • 1997
  • The theory of characteristic modes for coaxial waveguide with periodic axial slots is used to derive the weighted eigenvalue equation for calculating the characteristic values and the characteristic currents. Once the characteristic values and the characteristic currents are obtained, the important quantities such as the equivalent magnetic current, radiation patterns, and RCS are determined. Numerical results of the equivalent magnetic currents, radiation patterns, and RCS are compared with those obtained by use of the method of moments. A fairly good correspondence is observed between them.

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Comparison with SAR Patterns of Biological Objects Contacted with Coaxial Waveguide Antenna Using MUR and GPML ABCs in the FDTD Method (유한차분법에서 MUR과 GPML 흡수경계조건을 이용한 동축 도파관 안테나에 접촉된 생체의 SAR 패턴 비교)

  • 구성모;권광희;이창원;원철호;조진호
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.9 no.2
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    • pp.149-158
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    • 1998
  • The SAR patterns of biological objects contacted with coaxial waveguide antennal has been investigated, in which the biological object was modeled by a homogeneous and four-layered lossy human body. We derived the finite-difference time-domain(FDTD) algorithm and equation of MUR and generalized perfectly matched layer(GPML) ABCs in cylindrical coordination. The coupling between coaxial waveguide antenna and a biological object was analyzed by use of MUR and GPML ABCs in the FDTD method to obtain the absorbed power patterns in the media. The specific absorption rates (SAR) distribution which was corresponding to the temperature distribution was calculated in each region by use of the steady-state response in the FDTD method. The SAR patterns of the FDTD method using MUR absorbing boundary conditions(ABCs) was compared with those of the FDTD method using GPML ABCs. The comparison exhibits that the penetration depth of the SAR patterns using MUR ABCs is deeper than that of the SAR patterns using GPML ABCs because of loss in free space. However, the spread in the lateral directions of the SAR patterns using GPML ABCs is smaller than of the SAR patterns using MUR ABCs.

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Leaky-Wave Radiation from a Coaxial Waveguide with Periodic Circumferential Slots

  • Lee, Kyung-Bo;Lee, Chang-Won;Kim, Joong-Pyo;Son, Hyon
    • Proceedings of the IEEK Conference
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    • 1998.06a
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    • pp.157-160
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    • 1998
  • The analysis of a coaxial cable with periodic slots as a leaky-wave antenna is considered. The mode matching method and method of moments with Galerkin testing procedure is then used to obtain the determinantal equation for the unknown leaky-wave propagating constant. Both technigues allow the fields to be obtained in any region, and the radiation characteristics of the structure. By resorting to a suitable numerical techniques, it is possible to calculate the leaky-wave propagating constants and the radiation patterns. Numerical results demonstrate the validity of the technique.

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