Dielectric Permittivity Model for Polymer–Filler Composite Materials by the Example of Ni- and Graphite-Filled Composites for High-Frequency Absorbing Coatings

Artem Prokopchuk,Henning Heuer,Ivan Zozulia,Dmytro Tatarchuk,Yurii Didenko,Yuriy Poplavko

doi:10.3390/coatings11020172

Abstract

The suppression of unnecessary radio-electronic noise and the protection of electronic devices from electromagnetic interference by the use of pliable highly microwave radiation absorbing composite materials based on polymers or rubbers filled with conductive and magnetic fillers have been proposed. Since the working frequency bands of electronic devices and systems are rapidly expanding up to the millimeter wave range, the capabilities of absorbing and shielding composites should be evaluated for increasing operating frequency. The point is that the absorption capacity of conductive and magnetic fillers essentially decreases as the frequency increases. Therefore, this paper is devoted to the absorbing capabilities of composites filled with high-loss dielectric fillers, in which absorption significantly increases as frequency rises, and it is possible to achieve the maximum frequency selective of absorption due to electromagnetic and electromechanical resonances.

Highlights

Cell phones use frequencies of up to 2 GHz, miscellaneous radars work in frequency bands of 3–40 GHz, local telephone communication successfully uses a frequency range of approximately 60 GHz, and car radars operate at frequencies of approximately 80 GHz
A polymer with a complex dielectric constant ε* = 3.78 − j7.1·10–4 was used as the matrix material
The nickel powder particles had an average size of 60 microns, while the graphite filler particles had an average size of 100 microns according to the datasheet

Summary

Introduction

High-frequency bands are widely used in electronics and information technologies. 5G communication standards, which will eventually substitute 4G due to better spectral efficiency and will add to Long-Term Evolution (LTE) capabilities due to lower latency, are going to heavily utilize millimeter-bandwidth frequencies, up to 300 GHz [1]. They are going to be highly integrative [2] and will surely contribute to the Internet of Things, which is predicted to grow to up to 50 billion interconnected devices by 2030 [3]

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