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Engineering Science in
Additive Manufacturing AM-CFRP structures for EMWA properties

This review article summarizes the EMWA properties where Z is the input impedance, Z is the free-space
in
o
of CFRP composites, focusing on experimental research impedance, μ is the complex permeability, ɛ is the complex
r
r
and material design strategies. The paper also examines permittivity, j is an imaginary unit, c is the speed of light
key factors influencing mechanical and EMWA in vacuum, f is the frequency of the electromagnetic wave,
performance, including CFRP preparation techniques, and d is the thickness of the EMA material.
fiber orientation, distribution, and volume fraction, as well
as methods to enhance microwave absorption capabilities. 2.2. Attenuation constant
A comparative analysis of various CFRP modification The degree to which the EMA material can absorb the
approaches highlights the trade-offs between strategies, electromagnetic wave is indicated by the attenuation
offering insights into optimizing material properties for coefficient α, which shows the electromagnetic wave’s
specific applications. The review article also explores future attenuation ability per unit length. A significant
research directions to develop advanced CFRP-based portion of the electromagnetic wave energy within
EMWA composites for industrial use, emphasizing the the targeted frequency range must be absorbed by the
potential to address current challenges and inspire further EMA material and converted into other types of energy.
innovation in high-performance EMWA materials.
Typically, Equation II is used to calculate the attenuation
2. Electromagnetic microwave absorption coefficient:
mechanism 2 f 2 2
''
' '
' '
+
−
''
+
''
Figure 1 illustrates the reflection, refractive index, and α = c × (   − ' ' ) (    ) (   +  )
scattering of electromagnetic waves that strike an object’s (II)
surface. The term “EMA material” is a classification
material that can both absorb and project electromagnetic where f electromagnetic wave frequency, c is the speed of
wave energy onto their surface and significantly light in a vacuum, ε ′ is the real part of complex permittivity,
attenuate the energy received on their surface. It ε ′′ is the imaginary part of complex permittivity, µ ′ is the
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reduces electromagnetic wave interference by reflecting, real part of complex permeability, and µ ′′ is the imaginary
refracting, and scattering little energy. Matching part of complex permeability.
properties and attenuation characteristics are the main
requirements for materials to achieve effective EMA. 2.3. Reflection loss
The EMWA mechanism for fiber-reinforced polymer When waves are reflected, reflection loss takes place,
constructions that are additively built is summarized in necessitating an effective shield to deflect most incident
Table 1. electromagnetic waves. When charged particles in a
2.1. Impedance matching conductive substance interact with the electromagnetic
field, reflection loss results. The amount of loss energy
Equation I is typically used to compute the impedance is correlated with the material’s magnetic permeability
matching, which represents the human-emitted concerning a vacuum (μ ) and electrical conductivity (σ ).
electromagnetic wave’s capacity for reflection. Generally, the percentage of electromagnetic waves that
r
r
result in reflection losses increases with an EMA material’s
Z in r tanh j 2 fd (I) electrical conductivity and decreases with its magnetic

Z o r c rr permeability.

Figure 1. Electromagnetic wave interaction and absorption mechanism. Copyright © 2020 Elsevier. Reproduced with permission of Elsevier.
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Volume 1 Issue 2 (2025) 3 doi: 10.36922/ESAM025160008