• Title, Summary, Keyword: inverse electromagnetic problem

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Source Identification in 2-Dimensional Scattering Field Based on Inverse Problem (역문제를 이용한 2차원 산란장에서의 소스 추정)

  • Kim, Tae Yong;Lee, Hoon-Jae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.6
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    • pp.1262-1268
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    • 2014
  • Inverse problem is very interest in the sciences and engineering, in particular for modeling and monitoring applications. By applying inverse problem, it can be widely used to exploration of mineral resources, identification of underground cables and buried pipelines, and diagnostic imaging in medical area. In this paper, we firstly consider 2-dimensional EM scattering problem and present the FDTD method to estimate unknown source. In this case, non-linear CGM technique is used to investigate unknown sources corresponding to measured data obtained from forward problem in near field. The proposed technique for solving the inverse source problem presents a reasonable agreement and can be applied to investigate an internal source signal of embedded security module.

Solution of the Inverse Electromagnetic Scattering Problem for Cylindrical Objects by Using the Resonance Scattering Ttheory (공진산란이론을 이용한 원통형 산란체에 대한 전자기파문제의 역산란 이론)

  • Jung, Yong-Hwa;Jeon, Sang-Bong;Ahn, Chang-Hoi
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.55 no.3
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    • pp.142-148
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    • 2006
  • The resonances that contain the information on the properties of the scattering target can be used for target reconstruction approaches. The inverse scattering theory for the resonances has been applied to the problems of the scattering for a spherical, cylindrical dielectric objects and dielectrically coated conductors, shown reasonable results. Though by using this method the thickness and the dielectric constants of the target can be obtained from a determination of the spacing and of the widths of the scattering resonances, the radius of the target should be given. In this paper, we suggest the improved inverse theory combined with the resonance scattering theory to obtain the radius in addition to the dielectric constant of the target. The applications of this method for scattering problems of electromagnetic waves from cylindrical targets were accomplished, and it shows its validity.

3D Microwave Breast Imaging Based on Multistatic Radar Concept System

  • Simonov, Nikolai;Jeon, Soon-Ik;Son, Seong-Ho;Lee, Jong-Moon;Kim, Hyuk-Je
    • Journal of electromagnetic engineering and science
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    • v.12 no.1
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    • pp.107-114
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    • 2012
  • Microwave imaging (MI) is one of the most promising and attractive new techniques for earlier breast cancer detection. Microwave tomography (MT) realizes configuration of a multistatic multiple-input multiple-output system and reconstructs dielectric properties of the breast by solving a nonlinear inversion scattering problem. In this paper, we describe ETRI 3D MT system with 3D MI reconstruction program and demonstrate its robustness through some examples of the image reconstruction.

Solution of Gel'fand-Levitan-Marchenko Integral Equation with Restricted Inverse Scattering Potential and Its Applications to Synthesis of Dielectric Constant Distribution (제한된 범위의 역산란 포텐셜을 갖는 Gel'fand-Levitan-Marchenko 적분방정식의 해와 유전율 분포 합성에의 응용)

  • Jang, Wan-Gyu;Jung, Hyun-Soo;Park, Eui-Joon
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • pp.54-58
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    • 2003
  • In this study, the solution of Gel'fand-Levitan-Marchenko integral equation in the inverse scattering problem is efficiently solved for arbitrarily specified spectra pattern which are reflected from the restricted potential. The procedure is based on the successive approach without iterations. This method lessens the truncation errors which plague conventional design schemes using specific windows for reflection coefficients. It is shown that the method is adequate for the synthesis of the continuously varying one-dimensional potential of the nonuniformly distributed dielectric constants.

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A Study on the Efficient Synthesis of Nonuniform Transmission Line Filters using Zakharov-Shabat Coupled Mode Equation (Zakharov-Shabat 결합모드 방정식을 사용한 불균일 전송선로 필터의 효율적인 합성에 관한 연구)

  • 장완규;박의준
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.12
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    • pp.1283-1291
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    • 2003
  • Nonuniform transmission lines(NTLs) with the desired frequency response can be realized by synthesizing the potential from the coupled mode Zakharov-Shabat(ZS) equation in the one-dimensional inverse scattering problem. In this study, an efficient synthesis method using the ZS equations is presented for NTLs with arbitrarily specified reflection coefficients which take the restricted potential. This method lessens the line length which plague conventional design schemes using specific windows for reflection coefficients. Furthermore solving the ZS inverse transform problem is simplified by adopting the successive approach instead of the conventional iterative method. The proposed method is compared with the conventional method using specific windows by applying to design of dispersive NTL filters, and verified by two-port analysis through the chain matrix.

Optimal Design of Inverse Electromagnetic Problems with Uncertain Design Parameters Assisted by Reliability and Design Sensitivity Analysis

  • Ren, Ziyan;Um, Doojong;Koh, Chang-Seop
    • Journal of Magnetics
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    • v.19 no.3
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    • pp.266-272
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    • 2014
  • In this paper, we suggest reliability as a metric to evaluate the robustness of a design for the optimal design of electromagnetic devices, with respect to constraints under the uncertainties in design variables. For fast numerical efficiency, we applied the sensitivity-assisted Monte Carlo simulation (S-MCS) method to perform reliability calculation. Furthermore, we incorporated the S-MCS with single-objective and multi-objective particle swarm optimization algorithms to achieve reliability-based optimal designs, undertaking probabilistic constraint and multi-objective optimization approaches, respectively. We validated the performance of the developed optimization algorithms through application to the optimal design of a superconducting magnetic energy storage system.

Preclinical Prototype Development of a Microwave Tomography System for Breast Cancer Detection

  • Son, Seong-Ho;Simonov, Nikolai;Kim, Hyuk-Je;Lee, Jong-Moon;Jeon, Soon-Ik
    • ETRI Journal
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    • v.32 no.6
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    • pp.901-910
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    • 2010
  • As a supplement to X-ray mammography, microwave imaging is a new and promising technique for breast cancer detection. Through solving the nonlinear inverse scattering problem, microwave tomography (MT) creates images from measured signals using antennas. In this paper, we describe a developed MT system and an iterative Gauss-Newton algorithm. At each iteration, this algorithm determines the updated values by solving the set of normal equations using Tikhonov regularization. Some examples of successful image reconstruction are presented.

Control of One Dimensional Inverse Scattering Pattern and Its Applications (일차원 역산란 패턴 제어와 그 응용)

  • 최종인;박의준
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.2
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    • pp.291-301
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    • 1999
  • A method for the synthesis of one-dimensional nonlinear distribution function is presented for the desired inverse scattering pattern. This method is based on the inverse transform of the solution of the Riccati equation derived from one-dimensional inverse scattering problem. Since the solution is analogous to the array factor or normalized space factor in collinear array antenna, the synthesis method for field pattern is applied for the construction of the involved line-source nonlinear distribution function. The suggested method is carried out under the optimization process, and is numerically verified by synthesizing the dispersive transmission line profile within the specified frequency band and control of scattered field on resistive strip.

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Inverse Synthetic Aperture Radar Imaging Using Stepped Chirp Waveform (계단 첩 파형(Stepped Chirp Waveform)을 이용한 ISAR 영상 형성)

  • Lee, Seong-Hyeon;Kang, Min-Suk;Park, Sang-Hong;Shin, Seung-Yong;Yang, Eunjung;Kim, Kyung-Tae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.9
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    • pp.930-937
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    • 2014
  • Inverse synthetic aperture radar (ISAR) images can be generated by radar which radiates the electromagnetic wave to a target and receives signal reflected from the target. ISAR images can be widely used to target detection and recognition. This paper proposed a method of generation of high resolution ISAR images by synthesizing frequency spectrums of each stepped chirp waveform in one burst and sub-sampling in frequency domain. This process is performed over entire bursts during coherent processing interval. Conventional ISAR image generation method using stepped frequency waveform has a severe problem of short unambiguous range, loading to ghost phenomenon. However, this problem can be resolved by the proposed method. In simulations, we generate high resolution ISAR image of the moving target which is Boeing-737 aircraft model composed of several ideal point scatterers.