Near-Field Scanning-Based Shielding Effectiveness Extraction for Board-Level Shielding Cans


The conventional definition of shielding effectiveness (SE) is well suited for calculations of far-field electromagnetic shielding. However, in the near field, SE calculations are not as straightforward. In radio-frequency interference (RFI) problems, the majority of field coupling occurs in the near field. Thus, a well-defined method for calculating the near-field SE is needed to estimate the suppression of RFI achieved by shielding cans. In this study, a method based on near-field scanning is developed to extract the SE of board-level shielding cans. The SE is defined by modeling the shielded noise source as equivalent dipole moments. The accuracy of the equivalent source is analyzed via the least-square error and correlation coefficient as confidence verification parameters. By applying the reciprocity theorem, the voltage coupled on a planar inverted F antenna from an unshielded and a shielded source is calculated. The coupled voltage from a shielded noise source serves as a reference to validate the effectiveness of the proposed method. Practical shielding cans were used to develop and validate the SE extraction method using full-wave 3D simulations and measurements.


Electrical and Computer Engineering

Keywords and Phrases

Antenna Measurements; Correlation Coefficient; Coupling; Dipole Antennas; Dipole Moment; Integrated Circuit Modeling; Magnetic Noise; Magnetic Shielding; Mathematical Model; Near-Field Scanning; Planar Inverted F Antenna (PIFA); Radio Frequency; Radio-Frequency Interference (RFI); Reciprocity; Shielding Effectiveness (SE)

International Standard Serial Number (ISSN)

0018-9375; 1558-187X

Document Type

Article - Journal

Document Version


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© 2021 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Jan 2021