Attenuation in Extended Structures Coated With Thin Magneto-Dielectric Absorber Layer

Abstract

Abstract-Thin absorbing layers containing magnetic alloy or ferrite inclusions can be effectively used for attenuating common-mode currents on extended structures, such as power cords, cables, or edgecoupled microstrip lines. An analytical model to evaluate attenuation on the coaxial line with the central conductor coated with a magnetodielectric layer is proposed and validated by the experiments and numerical modeling. The analytical model is validated using available magneto-dielectric samples of different thicknesses. This model can serve for comparing and predicting the absorptive properties of different samples of magneto-dielectric materials, whose compositions may be unknown, but dielectric and magnetic properties can be determined by independent measurements over the specified frequency ranges. From modeling the absorption in a coaxial line with a wrapped central conductor, it could be concluded whether it is reasonable to use this particular material in such applications as a shield on an Ethernet or other cable, for reducing potential common-mode currents and unwanted radiation in the frequency range of interest.

EMI reduction evaluation with flexible absorbing materials and ferrite cores applied on cables

“…show that there is bigger difference between experiment and simulation results by 2D-FEM at the higher frequencies. One possible reason is that the 2D-FEM does not allow for modeling such fine effects as surface waves and their attenuation in the actual extended coated structure [15], [16]. As a result, there could be the lower standing wave ratio at higher frequencies in experiment compared to the modeled data due to actually higher loss in the experiment.…”

A Study of the Emc Performance of a Graded-Impedance, Microwave, Rice-Husk Absorber

“…It is a common practice to use metallic enclosures for electromagnetic attenuation, and different standards are available for their testing across a broad range of frequencies [30][31][32][33]. Microwave absorbers also can be characterized in terms of their shielding effectiveness [34], but, for the most part, their performance is described by their reflectivity with respect to a reference metallic plate. Figure 10.…”

Single Layered Wide Bandwidth Nanosized Strontium Hexa-Ferrite Filled Lldpe Absorber in X-Band

“…These absorbers were heavy and less resistant to corrosive environment [3]. Over the past decade, nano-sized magnetic materials have been increasingly used as inclusions for absorbers [4][5][6][7]. The reduced particle size splits the electronic energy level spacing which lies in the microwave range [8].…”