Preliminary design of magnetic shielding by FEM

Sasakawa, Takashi; Tagawa, Naoto; Herai, Toshiki; Tomita, Masaru

doi:10.1109/20.582675

Cited by 7 publications

(5 citation statements)

References 3 publications

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“…After some appropriate simplification, this optimization problem is formulated as a convex program of minimizing the sum of Euclidean norm under linear equality constraints. Plausibility of the model has been confirmed through previous research by one of the authors [23], where the problem was solved with a conventional iterative method and the result was compared with physical experiments. While the computational results seemed plausible, there was no guaranteed bound on the optimal value.…”

Section: Introduction Let Us Consider the Following Optimization Promentioning

confidence: 64%

“…In this subsection, we compare our result with the previous result obtained by one of the authors [23]. As is formulated in section 2, the magnetic shielding design problem is a problem of minimizing the sum of weighted Euclidean norm j∈E w j F * j subject to the linear constraint (2.3b).…”

Section: Comparison With the Previous Approachmentioning

confidence: 76%

“…Our purpose is to design magnetic shielding with minimum weight which has enough thickness at each point to shield passengers inside from the magnetic field generated by the SCM units. In the previous paper [23], one of the authors proposed a simplified design problem for magnetic shielding which minimizes the required magnetic materials for shielding. We explain it briefly in this subsection.…”

Section: Formulation Of a Simplified Optimal Magnetic Shielding Desigmentioning

confidence: 99%

“…We use B s = 1.5 Tesla throughout the paper. This value reflects the physical nature of the shielding material, which typically is iron or iron-based alloy, as was mentioned above and was used in [23]. Since the total weight of the shield material is proportional to its volume and the volume is given by integrating the thickness over the surface, the problem of minimizing the total weight of the shield material is formulated as the following optimization problem, which is a continuous version of minimizing the sum of Euclidean norm problem:…”

Section: Formulation Of a Simplified Optimal Magnetic Shielding Desigmentioning

confidence: 99%

“…As is formulated in section 2, the magnetic shielding design problem is a problem of minimizing the sum of weighted Euclidean norm j∈E w j F * j subject to the linear constraint (2.3b). In the previous paper [23], a solution of this problem was obtained by iteratively solving the following weighted least squares problem:…”

Section: Comparison With the Previous Approachmentioning

confidence: 99%

See 4 more Smart Citations

Optimal Magnetic Shield Design with Second-Order Cone Programming

Sasakawa¹,

Tsuchiya²

2003

SIAM J. Sci. Comput.

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In this paper, we consider a continuous version of the convex network flow problem which involves the integral of the Euclidean norm of the flow and its square in the objective function. A discretized version of this problem can be cast as a second-order cone program, for which efficient primal-dual interior-point algorithms have been developed recently. An optimal magnetic shielding design problem of the MAGLEV train, a new bullet train under development in Japan, is formulated as the continuous convex network flow problem and is solved with the primal-dual interior-point algorithm. Taking advantage of its efficiency and stability, we further apply the algorithm to robust design of the magnetic shielding.

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Section: Introduction Let Us Consider the Following Optimization Promentioning

confidence: 64%

Section: Comparison With the Previous Approachmentioning

confidence: 76%

Section: Formulation Of a Simplified Optimal Magnetic Shielding Desigmentioning

confidence: 99%

Section: Formulation Of a Simplified Optimal Magnetic Shielding Desigmentioning

confidence: 99%

Section: Comparison With the Previous Approachmentioning

confidence: 99%

See 3 more Smart Citations

Optimal Magnetic Shield Design with Second-Order Cone Programming

Sasakawa¹,

Tsuchiya²

2003

SIAM J. Sci. Comput.

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Numerical Methods for Shielding Analyses

2022

Electromagnetic Shielding

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Experimental study of SAR reduction on commercial products and shielding materials in mobile phone applications

Fung

Leung

Chan

2003

Micro & Optical Tech Letters

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ABSTRACT:There has been a recent increase in public concern regarding human safety due to the exposure of humans to radio frequency (RF) INTRODUCTIONAccording to the Office of the Telecommunications Authority in Hong Kong, the penetration rate of local mobile telephone services increased from 2. 3% in 19903% in to 85% in April 2002. Due to this rapid growth in the use of mobile phones and other wireless communication systems, public concern regarding the exposure of humans to radio frequency (RF) electromagnetic radiation has recently increased. This is particularly evident in the case of mobile telephone handsets and associated devices. As a result, many countries, such as Australia, Canada, Korea, and Japan, have provided various guidelines and standards that specify safety levels for such exposure to RF radiation. In the United States, the IEEE standard C95.1:1999 [2] specifies a recommended safety limit for human exposure to RF electromagnetic fields from 3 kHz to 300 GHz. In Europe, the International Commission on NonIonizing Radiation Protection (ICNIRP) has published guidelines, which are generally followed by the published standard EN50360: 2001 [3]. In Hong Kong, the mobile communications systems (GSM900, GSM1800) are similar to those in European countries. Therefore, the SAR limit of the European Standard will be used as a safety guideline for mobile phones. The European standards for testing mobile phones, EN50360:2001 and EN50361:2001, were published in July 2001. They specify the compliance of mobile phones with respect to SAR related to human exposure to electromagnetic fields ranging from 300 MHz to 3 GHz, including both basic restrictions on SAR and measurement methods.The specific absorption rate (SAR), used in the assessment of mobile phone handsets, is a measure of the amount of electromagnetic energy absorbed by biological tissue, particularly in the human body. For example, the SAR limit specified in IEEE C95.1: 1999 is 1.6 W/kg in a 1-g averaging mass, while that specified in the ICNIRP guidelines is 2 W/kg in a 10-g averaging mass. The induced SAR of a RF transmitting device is obtained by measuring the electric field in simulated human tissue in close proximity to the device, and is calculated by the formulawhere E i is the rms value of the electric field strength in the tissue V/m, is the conductivity of body tissue in S/m, and is the density of body tissue in kg/m 3 . The calculation of the SAR distribution in the human head, eye, and ear caused by a mobile phone using numerical methods has been discussed in various papers [4 -7].Products are available for SAR reduction which add external shields to mobile phones, particularly near the earpiece of the handsets. Materials, such as conductive mesh, conductive fabric, and conductive foam are now available and have been displayed in recent EMC exhibitions. These materials can also be applied to reduce the SAR of mobile phone handsets. There has also been some recent investigation into the shielding effectiveness of wiremesh screens and...

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Preliminary design of magnetic shielding by FEM

Cited by 7 publications

References 3 publications

Optimal Magnetic Shield Design with Second-Order Cone Programming

Optimal Magnetic Shield Design with Second-Order Cone Programming

Numerical Methods for Shielding Analyses

Experimental study of SAR reduction on commercial products and shielding materials in mobile phone applications

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