Double Layer Material Designed to Reduce Electromagnetic Radiation with Carbon Black, Silicon Carbide and Manganese Zinc Ferrite

Ariane Aparecida Teixeira de Souza,Matheus Carvalho Bispo,Mauricio Ribeiro Baldan,Nila Cecília de Faria Lopes Medeiros,Gisele Aparecida Amaral-Labat,Alan Fernando Ney Boss,Guilherme Frederico Bernardo Lenz e Silva,Leonardo Iusuti de Medeiros

doi:10.1590/jatm.v13.1199

Abstract

Radar absorbing materials (RAMs) are composites made with a polymeric matrix and an electromagnetic absorbing filler, such as carbon black (CB), silicon carbide (SiC) or manganese zinc ferrite (MnZn). To enhance their performances to attenuate an incident wave through reflection loss (RL), RAMs can be produced in multilayer structures. Usually, the RL analysis is done theoretically and experimentally validated with free space analysis. Here, it was demonstrated that multilayer structure can be designed and easily validated using rectangular waveguide, using a simpler setup and small samples. Three composites were produced using 2 wt% of CB (CB2), 40 wt% of SiC (SiC40) and 60 wt% of MnZn (MnZn60). They were characterized over the Ku-band and used to validate the multilayer structures, that were prepared by simply stacking each material inside the waveguide sample holder. One of the best results was obtained with structure SiC40+CB2 with 5.85 mm thickness, that presented a calculated RL of -21 dB at 17.8 GHz and a measured RL of -36 dB at the same frequency. In conclusion, using rectangular waveguide has been proven to be an easy, cheap, precise and fast approach to validate multilayer structures designs.

Highlights

Radar absorbing materials (RAMs) are materials designed to reduce the electromagnetic reflection over a frequency range
Morphological characteristics such as grain size and geometry were evaluated through scanning electron microscope (SEM) images of silicon carbide (SiC), carbon black (CB) and manganese zinc ferrite (MnZn) ferrite (Fig. 3)
Carbon black presented a characteristic cluster of nanometric spheres, and MnZn ferrite showed faceted particles ranging from 10 to 50 μm

Summary

Introduction

Radar absorbing materials (RAMs) are materials designed to reduce the electromagnetic reflection (or transmission) over a frequency range. Several types of RAMs and absorbing structures have been developed over the decades, such as: single layer RAMs (Liu et al 2014a); multilayer RAMs (Datashvili et al 2006); frequency selective surface (Chung 2004; Vergara et al 2019); and others (Ahmad et al 2019). These materials can be used to protect electronics from the electromagnetic pollution created by thousands of Received: Jun. 25, 2020 | Accepted: Nov. 17, 2020 Peer Review History: Double-blind Peer Review.

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