• Title, Summary, Keyword: Artificial Magnetic Conductor

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Design of Miniaturized Dual-Band Artificial Magnetic Conductor with Easy Control of Second/First Resonant Frequency Ratio

  • Ta, Son Xuat;Park, Ikmo
    • Journal of electromagnetic engineering and science
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    • v.13 no.2
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    • pp.104-112
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    • 2013
  • A novel miniaturized artificial magnetic conductor (AMC) is proposed for dual-band operation. An AMC unit cell that employs four slots in the metallic patch is used to achieve miniaturization as well as easy control of the second/first resonant frequency ratio, which can be varied from 1.5 to 3.26 by simply changing the slot shape for a given metallic patch size. A dual-band antenna composed of a wideband monopole suspended over the proposed AMC surface is designed and tested to validate this approach. The measurements result in a satisfactory and good matching condition for the dual-band antenna.

Design of Frequency Selective Surface Based Artificial Magnetic Conductor Using the Particle Swarm Optimization (PSO를 이용한 주파수 선택 구조 기반 인공 자기 도체 설계)

  • Hong, Ic-Pyo;Lee, Kyung-Won;Yook, Jong-Gwan;Cho, Chang-Min;Chun, Hueng-Jae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.6
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    • pp.610-616
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    • 2010
  • In this paper, particle swarm optimization(PSO) is applied for the design of frequency selective surface based artificial magnetic conductor. An equivalent circuit model for this artificial magnetic conductor(AMC) with Jerusalem Cross arrays was derived and then PSO was applied for obtaining the optimized geometrical parameters with desired resonant frequency. The resonant frequency and the reflection phase characteristics from the optimization were compared to the results from commercial software for verifying the validity of this paper. The procedure presented in this paper can be applied to design the AMC with different frequency selective surface and also can be used for the design of microwave circuits like the AMC ground planes.

Non-contact critical current measurement of superconducting coated conductor using Hall Probe (Hall Probe를 이용한 초전도선재의 비접촉 임계전류 측정 방법)

  • Kim, Ho-Sup;Oh, Sang-Soo;Lee, Nam-Jin;Ha, Dong-Woo;Baik, Seung-Kyu;Ko, Rock-Kil;Ha, Hong-Soo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.12-12
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    • 2010
  • The hall probe measurement system was used to measure the critical current distribution of superconducting coated conductor. The system consists of reel to reel moving apparatus, 7 array hall probe, a rotary encoder and permanent magnet. The magnetic field profile across the width of superconducting coated conductor using Bean's critical state model was calculated. The effect of various parameters of the formulas on the magnetic field distribution and the effect of shape and size of artificial defects, which were formed on the surface of SmBa2Cu3O7-d(SmBCO) coated conductor using laser marking system, on the hall probe magnetic field signal of the hall probe measurement system was investigated.

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TM Mode Analysis of a Periodic Thick Mushroom Structure

  • Woo, Dae Woong;Park, Wee Sang
    • International journal of advanced smart convergence
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    • v.1 no.2
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    • pp.43-46
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    • 2012
  • We analyzed a periodic thick mushroom structure for use as an artificial magnetic conductor using mode-matching method. The fields in each region were represented by either Floquet modes or waveguide modes. By applying tangential electric and magnetic field continuity conditions and using matrix equations, unknown coefficients and dispersion diagram were calculated. The proposed model can account for the effects of oblique incidence. Simulation time using the method was much faster than the commercial tools. We found that the current method produces accurate results of reflection phase and dispersion diagram.

Design of Scan-Capable Fabry Perot Cavity Antenna Using Artificial Magnetic Conductors (인공 자기 도체를 이용한 스캔 가능한 패브리 패롯 공진기형 안테나 설계)

  • Kim, Myong-Gyun;Kim, Jong-Sung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.9
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    • pp.1025-1033
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    • 2012
  • Fabry-Perot cavity(FPC) antennas with artificial magnetic conductor(AMC) surface are designed in order to provide scan capability by $4{\times}1$ array feed inside the cavity. The proposed antenna, excited by $4{\times}1$ thinned array, not only achieve higher directivities but also improve suppression of sidelobe level(SLL) relative to that of the thin array alone. The FPC antenna with the height of a quarter wavelength generate maximum gain of 19 dB, SLL suppression of 14 dB and maximum scan angle of $8^{\circ}$ under the feed phase difference of $90^{\circ}$ at the design frequency of 12 GHz.

The Radiation Characteristics Improvement and Thickness Reduction of Base Station Antenna with Artificial Magnetic Conductor (인공 자기 도체를 이용한 기지국 안테나의 방사 특성 개선 및 두께 감소)

  • Son, Cheol-Hong;Ahn, Ji-Hwan;Chang, Ki-Hun;Yoon, Ji-Hwan;Yoon, Young-Joong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.12
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    • pp.1233-1242
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    • 2009
  • In this paper, a Base Station Antenna(BSA) utilizing Artificial Magnetic Conductor(AMC) as reflector instead of common conductive plate to improve radiation characteristics and achieve low-profile is proposed. In the case of the conventional BSA on conductive surface which acts as a reflector, a secondary radiation is caused at the corner of the conductive surface, and it increases the back-lobe of the antenna, resulting in deteriorating the radiation characteristic of the conventional BSA. However, using the AMC, the back-lobe of the BSA can be largely reduced by the surface wave suppression. And the Side-Lobe Level(SLL) is also improved, resulting in preventing the service area overlapped. Furthermore, due to the $0^{\circ}$ reflection phase on AMC, the profile of the BSA can be also reduced.

Realization of High Impedance Surface Characteristics Using a Periodically Transformed Artificial Magnetic Conductor Structure and Reduction Technique of Specific Absorption Rate

  • Lee, Seungwoo;Rhee, Seung-Yeop;Kim, Pan-Yeol;Kim, Nam
    • Journal of electromagnetic engineering and science
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    • v.13 no.2
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    • pp.113-119
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    • 2013
  • We developed a transformed, symmetrical, mushroom-like surface without via holes in cells focused on a 2.4-GHz WLAN band. Each slot in the novel type structure plays a key role in modeling at the desired frequencies. The designed artificial magnetic conductor (AMC) has several advantages, including a small size, a wider bandwidth, a short reflecting distance to the antenna, and easy fabrication because there are no via holes. Overall dimensions of the AMC cell are 21 mm $(Width){\times}21mm$ $(Height){\times}2.6mm$ (Thickness), and the bandwidth is about three times wider (11.7%) compared to that of a conventional AMC (4.0%). For evaluating the performance of the proposed structure, a reflector, which periodically consists of the designed AMC cells, was developed. The antenna with the investigated AMC reflector not only works within a quarter of the wavelength because of the extremely high wave impedance generated by the AMC cells on the surface of the structure but also reduces the specific absorption rate (SAR). Electromagnetic field (EMF) exposure to a human phantom was analyzed by applying the designed reflector to the 2.4-GHz dipole antenna in a tablet PC. The calculated peak SAR averaged over 1 g was 0.125 W/kg when the input power was 1 W and the antenna was located at 20 cm from the human phantom. However, the SAR value was only 0.002 W/kg (i.e., 98.4% blocked) when the designed reflector was inserted in front of the antenna.

Artificial Magnetic Conductor(AMC) Polarizer Backed Circular-Polarized(CP) Antenna (인공 자기 도체 편파 변환기를 이용한 원형 편파 안테나)

  • Chang, Ki-Hun;Ahn, Ji-Hwan;Yoon, Young-Joong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.5
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    • pp.459-467
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    • 2010
  • A new type of circularly polarized(CP) antenna that is characterized by having both low-profile and greater axial-ratio bandwidth(ARBW) beyond existing antennas is introduced through analysis of artificial magnetic conductor(AMC) polarizer, and experimentally demonstrated. Although it is made use of a linear-polarized dipole antenna with close proximity to ground plane, it is backed by AMC polarizer so as to efficiently radiate with circularly changed polarization whose ARBW is determined by the texture geometry, whereas existing antennas exhibit CP surface-current on radiators, which limit ARBW. The mechanism of the polarization conversion is theoretically analyzed for ARBW, and the experimental properties including the impedance matching, CP radiation pattern, axial-ratio pattern, ARBW, and two-port isolation are discussed.

Analysis of AMC Characteristics According to Material Constants and Correlation of Dipole Antenna (유전율 및 투자율에 따른 인공자계도체 특성 및 다이폴 안테나 간 상관관계 분석)

  • Lee, Donghyun;Min, Taehong;Lee, Jongmoo
    • Journal of the Korea Society for Simulation
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    • v.29 no.1
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    • pp.23-30
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    • 2020
  • In this paper, we theoretically examine the characteristics of an Artificial Magnetic Conductor (AMC) constructed of a perfect electric conductor and a normal material having permittivity εr, permeability μr, and thickness L. First, we derived rigorous equations to describe the infinite AMC structure. Then, we studied how the AMC's characteristics are affected by changes in εr, μr and L. The operating center frequency exhibiting a 0° reflection coefficient phase occurs when L is one quarter of a guide wavelength. Therefore, the AMC thickness can be reduced by using a material having a high product of εr and μr. As the ratio μr/εr increases, the bandwidth of the AMC increases (maximum value: 200 %), and its operating frequency decreases. We also find out he bandwidth of the AMC is improved by introducing a loss in the material. To validate the AMC, we design a dipole antenna on the AMC and demonstrate a relationship between AMC phase and dipole antenna's operating frequency by investigating the dipole on the AMC with different pairs of εr and μr.

Characteristics of a dipole on AMC consisting of a normal material and a ground plane (일반 물질과 접지면으로 구성된 AMC 위의 다이폴 안테나 특성 분석)

  • Lee, Dong-Hyun;Woo, Dea-Woong;Kim, Gi-Ho;Ji, Jeong-Keun;Seong, Won-Mo;Park, Wee-Sang
    • Proceedings of the IEEK Conference
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    • pp.347-348
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    • 2008
  • We investigate the characteristics of a dipole antenna on an artificial magnetic conductor (AMC) constructed of a normal material and a ground plane. We studied how the antenna performance is affected by changes in the dipole length and the distance between the dipole and the ground plane. The relation between the reflection phase of the AMC and the input resistance of the dipole for input impedance matching is also verified.

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