Rigorous Analysis of a Loop Antenna System for Magnetic Interference Measurement


IEICE TRANSACTIONS on Communications   Vol.E76-B    No.1    pp.20-28
Publication Date: 1993/01/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Antennas and Propagation
EMC,  EMI measurement,  loop antenna system,  large loop antenna,  

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Theoretical and actual experimental investigations are made on a Loop Antenna System (LAS) consisting of N-gap loop antennas. A general formula for the LAS response to an external EM field is derived by using both the method of moments and techniques for transmission-line analysis. Numerical evaluation verifies that the LAS has favorable characteristics, such as invariable response within a wide frequency range. In addition, differences between the LAS method and the present open-field method in the results of measurement are evaluated. It should be noted that the LAS gives a much lower output for an electrical source than for a magnetic source, even if both sources produce the same value with the open-field method. It is concluded that conversion factors for the results from the LAS method to the open-field method strongly depend on the orientation of the source as well as its characteristics. Consequently, new conversion factors are proposed to obtain practical EMI measurements.