Approximate Formulas for Shielding Effectiveness of an Infinite Planar Shield for Dipole Fields

Yoshifumi AMEMIYA; Takashi YAMAGUCHI

Approximate Formulas for Shielding Effectiveness of an Infinite Planar Shield for Dipole Fields

Yoshifumi AMEMIYA, Takashi YAMAGUCHI

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This paper presents a relationship between the near-field shielding effectiveness (SE) and the far-field SE of an infinite planar shield for dipole fields. The penetration fields through the shield and the near-field SE are deduced analytically from an explicit integral expression based on certain assumptions. They further give us approximate formulas for the near-field SE. The near-field SE depends on not only wavelength and material used, but also on the distance r from a source to an observation point through the shield, the source type (magnetic dipole or electric dipole) and the orientation (vertical or horizontal to the shield face) in general. The results we obtained are as follows. The near-field SE for magnetic dipole fields vertical to the shield face is the same as that horizontal to the shield face, and their absolute values equal that of the far-field SE multiplied by k₀r/3 (k₀ is the wave number). The near-field SE for electric dipole fields vertical to the shield face doubles that horizontal to the shield face, and the absolute value of the latter equals that of the far-fields SE divided by k₀r. The validity of the assumptions used to obtain the approximate formulas are examined. The range of r (an application range), over which the difference between the approximate value and the true value is under 1 dB, is determined, where the former value is calculated by the approximate formula of the SE and the latter value is etsimated by direct integration of the related integral expression. For instance, an application range of the approximate formula for magnetic dipole fields vertical to the shield face is from larger one of 50δ and 33µ_rδ to 0. 11λ₀, where µ_r is specific permeability, δ is skin depth of the shielding material used and λ₀ is wavelength in the free space.

Publication: IEICE TRANSACTIONS on Communications Vol.E81-B No.11 pp.2219-2228

Publication Date: 1998/11/25

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Category: Electromagnetic Compatibility

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Yoshifumi AMEMIYA, Takashi YAMAGUCHI, "Approximate Formulas for Shielding Effectiveness of an Infinite Planar Shield for Dipole Fields" in IEICE TRANSACTIONS on Communications, vol. E81-B, no. 11, pp. 2219-2228, November 1998, doi: .
Abstract: This paper presents a relationship between the near-field shielding effectiveness (SE) and the far-field SE of an infinite planar shield for dipole fields. The penetration fields through the shield and the near-field SE are deduced analytically from an explicit integral expression based on certain assumptions. They further give us approximate formulas for the near-field SE. The near-field SE depends on not only wavelength and material used, but also on the distance r from a source to an observation point through the shield, the source type (magnetic dipole or electric dipole) and the orientation (vertical or horizontal to the shield face) in general. The results we obtained are as follows. The near-field SE for magnetic dipole fields vertical to the shield face is the same as that horizontal to the shield face, and their absolute values equal that of the far-field SE multiplied by k₀r/3 (k₀ is the wave number). The near-field SE for electric dipole fields vertical to the shield face doubles that horizontal to the shield face, and the absolute value of the latter equals that of the far-fields SE divided by k₀r. The validity of the assumptions used to obtain the approximate formulas are examined. The range of r (an application range), over which the difference between the approximate value and the true value is under 1 dB, is determined, where the former value is calculated by the approximate formula of the SE and the latter value is etsimated by direct integration of the related integral expression. For instance, an application range of the approximate formula for magnetic dipole fields vertical to the shield face is from larger one of 50δ and 33µ_rδ to 0. 11λ₀, where µ_r is specific permeability, δ is skin depth of the shielding material used and λ₀ is wavelength in the free space.
URL: https://global.ieice.org/en_transactions/communications/10.1587/e81-b_11_2219/_p

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@ARTICLE{e81-b_11_2219,
author={Yoshifumi AMEMIYA, Takashi YAMAGUCHI, },
journal={IEICE TRANSACTIONS on Communications},
title={Approximate Formulas for Shielding Effectiveness of an Infinite Planar Shield for Dipole Fields},
year={1998},
volume={E81-B},
number={11},
pages={2219-2228},
abstract={This paper presents a relationship between the near-field shielding effectiveness (SE) and the far-field SE of an infinite planar shield for dipole fields. The penetration fields through the shield and the near-field SE are deduced analytically from an explicit integral expression based on certain assumptions. They further give us approximate formulas for the near-field SE. The near-field SE depends on not only wavelength and material used, but also on the distance r from a source to an observation point through the shield, the source type (magnetic dipole or electric dipole) and the orientation (vertical or horizontal to the shield face) in general. The results we obtained are as follows. The near-field SE for magnetic dipole fields vertical to the shield face is the same as that horizontal to the shield face, and their absolute values equal that of the far-field SE multiplied by k₀r/3 (k₀ is the wave number). The near-field SE for electric dipole fields vertical to the shield face doubles that horizontal to the shield face, and the absolute value of the latter equals that of the far-fields SE divided by k₀r. The validity of the assumptions used to obtain the approximate formulas are examined. The range of r (an application range), over which the difference between the approximate value and the true value is under 1 dB, is determined, where the former value is calculated by the approximate formula of the SE and the latter value is etsimated by direct integration of the related integral expression. For instance, an application range of the approximate formula for magnetic dipole fields vertical to the shield face is from larger one of 50δ and 33µ_rδ to 0. 11λ₀, where µ_r is specific permeability, δ is skin depth of the shielding material used and λ₀ is wavelength in the free space.},
keywords={},
doi={},
ISSN={},
month={November},}

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TY - JOUR
TI - Approximate Formulas for Shielding Effectiveness of an Infinite Planar Shield for Dipole Fields
T2 - IEICE TRANSACTIONS on Communications
SP - 2219
EP - 2228
AU - Yoshifumi AMEMIYA
AU - Takashi YAMAGUCHI
PY - 1998
DO -
JO - IEICE TRANSACTIONS on Communications
SN -
VL - E81-B
IS - 11
JA - IEICE TRANSACTIONS on Communications
Y1 - November 1998
AB - This paper presents a relationship between the near-field shielding effectiveness (SE) and the far-field SE of an infinite planar shield for dipole fields. The penetration fields through the shield and the near-field SE are deduced analytically from an explicit integral expression based on certain assumptions. They further give us approximate formulas for the near-field SE. The near-field SE depends on not only wavelength and material used, but also on the distance r from a source to an observation point through the shield, the source type (magnetic dipole or electric dipole) and the orientation (vertical or horizontal to the shield face) in general. The results we obtained are as follows. The near-field SE for magnetic dipole fields vertical to the shield face is the same as that horizontal to the shield face, and their absolute values equal that of the far-field SE multiplied by k₀r/3 (k₀ is the wave number). The near-field SE for electric dipole fields vertical to the shield face doubles that horizontal to the shield face, and the absolute value of the latter equals that of the far-fields SE divided by k₀r. The validity of the assumptions used to obtain the approximate formulas are examined. The range of r (an application range), over which the difference between the approximate value and the true value is under 1 dB, is determined, where the former value is calculated by the approximate formula of the SE and the latter value is etsimated by direct integration of the related integral expression. For instance, an application range of the approximate formula for magnetic dipole fields vertical to the shield face is from larger one of 50δ and 33µ_rδ to 0. 11λ₀, where µ_r is specific permeability, δ is skin depth of the shielding material used and λ₀ is wavelength in the free space.
ER -