Frequency Selective Surface Properties of Microwave New Absorbing Porous Carbon Materials Embedded in Epoxy Resin

Abstract

In this manuscript, the electromagnetic wave absorption properties of sustainable porous carbon composites were evaluated over the X-band frequency range (8.2-12.4 GHz). The porous carbon material was made from the byproduct of cellulose production and was used as additive on the development of radar absorbing material (RAM) composites. These porous carbon materials have different characteristics, such as porosity size (180 m < Ø 1 < 250 m and 425 m < Ø 2 < 500 m) and particle size (ϕ 1 < 250 m and 250 m < ϕ 2 < 425 m). Composite materials were also studied as frequency selective surface (FSS) structures. It was shown how complex permittivity and reflection loss (RL) can be manipulated over the frequency range using FSS structure. While regular RAM presented RL of 19 dB at ~11.8 GHz, FSS structure presented a RL of 19 dB shifted to 12.4 GHz regarding the same carbon porous material (with particles between 250 and 425 µm and porosity between 180 and 250 µm). It was demonstrated here the potential use of sustainable porous carbon as RAM, and how FSS structure can be used to tune the frequency of the RL maximum peak.

Sustainable Carbon Xerogel in the Production of Electromagnetic Radar Absorbing Composites in the Ku-Band

“…This effect can be attributed to a polarization interface due to the creation of dipoles between the CX interface and the polymer matrix 61,62 . The increase in the ε'', shown in Figure 9d, might be related to an increase in electrical conductivity, probably related to the higher concentration of porous carbon 29,63 .…”

“…The complex permittivity of all samples 10CX, 15CX, 10CX/0.1CNT, and 15CX/0.1CNT are illustrated in Figure 9. The real (ε') and imaginary parts (ε'') of permittivity are related to the capacitive and dissipative effects in the material 29,41 .…”

“…Thus, a substantial lack of information concerning such materials in this field is clear. Most works on this topic apply carbon foams as RAM [29][30][31][32] at several frequencies including the X-band (8-12.4 GHz) and the Ka-Band (27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40). Additionally, electromagnetic characterization of biosourced materials is also scarce in the frequency range of 12.4-18 (Ku-Band), usually applied to aircraft and aerospace applications, such as radar, high-performance aircraft, and coatings for satellite by preventing electromagnetic interference, among other applications [33][34][35][36][37][38] .…”

Improved Microwave Absorption Performance with Sustainable Porous Carbon/Carbon Nanotube Composites

“…The XRD analysis of PC particles and CNT are revealed in Figure 1d. It can be observed that CNT exhibit their main peaks at ~25° and smaller peaks at ~44°, which are assigned to the crystalline planes (002) and (100), respectively 2,27,35 . CNT still presents a small peak ~57° from a crystalline plane (004) related to the reflection of the second order of (001) 36,[43][44][45] .…”

“…Microwaves are very efficient for information transmission and are widely used in various communication technologies [1][2][3][4][5] . However, microwaves also produce electromagnetic interference in equipment and devices and can affect human health [6][7][8][9][10] .…”