Design optimization and fabrication of a wideband microwave absorber based on dual-phase dielectric semi-metallic nanocomposite

Investigations into the microwave shielding behavior of oriented Polycaprolactone/Carbonyl iron particles composites fabricated using magnetic field assisted extrusion 3D printing

“…Quan et al 18 utilized defect engineering to establish relationship between various factors responsible for the electromagnetic attenuation in absorber materials. Similar work has been put forth by various other researches [19][20][21][22][23][24][25][26][27][28][29][30][31] using different polymer composites made using graphene, silicon carbide, silver coated graphene, CNT, iron oxide, carbonyl iron, carbon fibre as filler particles and epoxy, polypyrrole, polyaniline, polypropylene, polycaprolactone as polymer matrix.…”

Design of Four Layer Microwave Absorber Based on Polyaniline-Expanded Graphite Composites: Role of Layer Interfaces in Impedance Matching

“…The analysis thus reveals that impedance matched-mismatched interface effect as a function of permittivity (filler concentration) for four layer design structure of developed dielectric materials promotes the structure for maximum absorption of designated frequency range as an efficient RAM (Radar Absorbing Material). Further, in comparison to authors earlier work, 6 which design predicted an RLc value of ∼−59 dB (double layer) having thickness 2.6 mm of absorber at 11.9 GHz with −20 dB microwave frequency absorption bandwidth of 2.4 GHz and (RLc) ∼ −34 dB (triple layer) with −20 dB absorption bandwidth >3.57 GHz in the X-band, 7 the present design approach shows a promising result with a higher value −20 dB absorption bandwidth of (2.5 GHz) towards the lower frequency range (10.69 GHz) in the X-band. Moreover, the study also reveals 1.36 and 2.35 times lower value in terms of RLc (= ∼−80 dB) and 1.07 and 1.85 times lower value in terms of RLm (= ∼−63 dB) over the double 6 and triple layer designs 7 respectively only just by compromising the thickness of RAM.…”

“…Further, in comparison to authors earlier work, 6 which design predicted an RLc value of ∼−59 dB (double layer) having thickness 2.6 mm of absorber at 11.9 GHz with −20 dB microwave frequency absorption bandwidth of 2.4 GHz and (RLc) ∼ −34 dB (triple layer) with −20 dB absorption bandwidth >3.57 GHz in the X-band, 7 the present design approach shows a promising result with a higher value −20 dB absorption bandwidth of (2.5 GHz) towards the lower frequency range (10.69 GHz) in the X-band. Moreover, the study also reveals 1.36 and 2.35 times lower value in terms of RLc (= ∼−80 dB) and 1.07 and 1.85 times lower value in terms of RLm (= ∼−63 dB) over the double 6 and triple layer designs 7 respectively only just by compromising the thickness of RAM. Fabrication and reflection loss measurement.-Based on optimized design using Transmission line model, the conductor backed four layer structure was fabricated as PG1-PG3-PG5-PA3 as layer 1, layer 2, layer 3 and layer 4 respectively with thicknesses d1 = 2.1 mm, d2 = 1.6 mm, d3 = 2.0 mm and d4 = 3.0 mm.…”

X-band metamaterial absorbers based on reduced graphene oxide-silicon carbide-linear low density polyethylene composite

“…As the dipole density and their orientation determine the polarizability of the composite material which in turn depends on the fillers concentration, so increase in frequency of the applied field results dipole relaxation because the large number dipoles present in the sample C unable to match their reorienting frequency with that of applied electric field in order to resist the oscillating field and as a result, complex permittivity of sample C declines with increasing frequency as in Figures 3a and 3b. Also interfacial polarization provides good support at lower frequency [40], with increase in frequency of applied field the tendency for the interfacial polarization [41] is also expected to be decreased resulting in decrease in polarizability and hence permittivity and loss factor. Because of high conductivity and polarization at RGO-SiC interfaces make it possible for electron transfer process [38] through dipole-dipole interactions by allowing electron hopping and transferring between the fillers and matrix, which also assists for microwave absorption.…”

“…Polarization and various intrinsic nature of composite material can thus be responsible for observed peaks in the plot of both the real (e r / (v) and imaginary e r // (v) parts of complex permittivity. Moreover, the frequency dependence composites complex permittivity behavior of various wt.% of RGO-SiC fillers can be analyzed through capacitor formalism of composites [41]. Polymer with inclusion of composite fillers may be regarded as a parallel network of large number of boundary layer parallel capacitors.…”