Next Article in Journal
Critical Factors for the Recycling of Different End-of-Life Materials: Wood Wastes, Automotive Shredded Residues, and Dismantled Wind Turbine Blades
Previous Article in Journal
Bi-layered Nanofibers Membrane Loaded with Titanium Oxide and Tetracycline as Controlled Drug Delivery System for Wound Dressing Applications
Previous Article in Special Issue
Comparison of Experimental and Modeled EMI Shielding Properties of Periodic Porous xGNP/PLA Composites
Open AccessArticle

Accurate Measurement of the True Plane-Wave Shielding Effectiveness of Thick Polymer Composite Materials via Rectangular Waveguides

Centre of Polymer Systems, University Institute, Tomas Bata University in Zlín, Trida T. Bati 5678, 760 01 Zlín, Czech Republic
Faculty of Applied Informatics, Tomas Bata University in Zlín, Nad Stráněmi 4511, 760 05 Zlín, Czech Republic
Author to whom correspondence should be addressed.
Polymers 2019, 11(10), 1603;
Received: 5 August 2019 / Revised: 16 September 2019 / Accepted: 27 September 2019 / Published: 1 October 2019
(This article belongs to the Special Issue Polymer Based Composites for Electromagnetic Interference Shielding)
This paper presents a methodology for accurately gauging the true plane wave shielding effectiveness of composite polymer materials via rectangular waveguides. Since the wave propagation of the waveguides is not in the form of plane wave patterns, it is necessary to post-process the S-parameters for the measured data of the waveguide lines to obtain such patterns and ascertain the effectiveness of true plane wave shielding. The authors propose two different methods to achieve this. The first applies simple renormalization of S-parameters, where reference impedance is changed from the value for the waveguide to that for free space, which ensures good accuracy of shielding effectiveness with a small degree of discontinuity across the range of frequencies. The other relies on rigorous extraction of the composite materials’ effective permittivity and permeability ascertained from rectangular waveguides; afterward, plane wave shielding effectiveness is calculated analytically and gives very high accuracy. Both procedures assume the given samples are isotropic in character. We validated the accuracy of the methodologies by conducting tests on a set of synthetic samples of 2 mm thickness with unit permittivity and variable conductivity and on a dielectric material of known permittivity (FR4 laminate). The applicability of both methods was further proven by analyzing the isotropic composite materials, a process involving the use of iron particles embedded in a dielectric matrix. The synthetic samples and an FR4 material were tested to check the accuracy of the methods. Based on numerical studies and measurements, we concluded that materials with a shielding effectiveness of up to 25 dB could be measured at a maximum amplitude error of 1 dB to 3dB to a frequency of 18 GHz, depending on the relative permittivity of the material; hence, the first method was suitable for approximation purposes. For maximal accuracy, the second method typically demonstrated an amplitude error of below 0.5 dB to the same frequency across the entire range. View Full-Text
Keywords: electromagnetic shielding; waveguide; composite material; permittivity; permeability electromagnetic shielding; waveguide; composite material; permittivity; permeability
Show Figures

Figure 1

MDPI and ACS Style

Moučka, R.; Goňa, S.; Sedlačík, M. Accurate Measurement of the True Plane-Wave Shielding Effectiveness of Thick Polymer Composite Materials via Rectangular Waveguides. Polymers 2019, 11, 1603.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

Back to TopTop