A new method to characterize microwave electromagnetic (EM) absorption of a bulk carbon nanotube (CNT) material is proposed and experimentally evaluated in this paper. The method is based on the measurement of microwave transmission through a capacitive-resonator aperture (CRA) in a conductive screen loaded with a CNT sample under test. This method allows us to measure microwave permittivity and absorption of thin samples (∼0.1 μm–10 μm thick) with linear dimensions much smaller than the wavelength of radiation in free space. This “minimal” sample requirement restricts the application of conventional microwave characterization methods such as free-space or waveguide permittivity characterization. It is demonstrated that the resonance E-field enhancement inside the CRA leads to strong EM interaction of the microwave E-field with the CNT sample under test, thus enabling high sensitivity and dynamic range (∼5 dB) of the measurement procedure. Another advantage of the proposed technique over conventional non-resonance characterization methods is that in the resonance transmission band, the CRA operation is reflection-less, which leads to a relatively simple qualitative algebraic de-embedding procedure of the material parameters based on the principle of energy conservation. The experimental microwave absorption data of the multiwall CNT samples are presented in the S frequency band (2–4 GHz), demonstrating microwave absorption properties of the multiwall CNT ribbons.

1.
J. N.
Wang
,
X. G.
Luo
,
T.
Wu
 et al, “
High-strength carbon nanotube fibre-like ribbon with high ductility and high electrical conductivity
,”
Nat. Commun.
5
,
3848
(
2014
).
2.
Carbon Nanotubes: Science and Applications
, edited by
M.
Meyyappan
(
CRC Press
,
2005
).
3.
Advanced Nanomaterials for Aerospace Applications
, edited by
C.
Cabrera
and
F.
Miranda
(
Pan Stanford Publishing
,
2014
).
4.
K. Y.
You
,
F. B.
Esa
, and
Z.
Abbas
, “
Macroscopic characterization of materials using microwave measurement methods—A survey
,” in
PIERS—FALL
,
194
204
(
IEEE
,
2017
).
5.
F.
Costa
,
M.
Borgese
,
M.
Degiorgi
, and
A.
Monorchio
, “
Electromagnetic characterisation of materials by using transmission/reflection (T/R) devices
,”
Electronics
6
,
95
(
2017
).
6.
H.
Zhang
,
G.
Zeng
,
Y.
Ge
,
T.
Chen
, and
L.
Hu
, “
Electromagnetic characteristic and microwave absorption properties of carbon nanotubes/epoxy composites in the frequency range from 2 to 6 GHz
,”
J. Appl. Phys.
105
(
5
),
054314
(
2009
).
7.
X.
Xia
,
Y.
Wang
,
Z.
Zhong
, and
G. J.
Weng
, “
A theory of electrical conductivity, dielectric constant, and electromagnetic interference shielding for lightweight graphene composite foams
,”
J. Appl. Phys.
120
,
085102
(
2016
).
8.
L.
Wang
and
Z.-M.
Dang
, “
Carbon nanotube composites with high dielectric constant at low percolation threshold
,”
Appl. Phys. Lett.
87
,
042903
(
2005
).
9.
A.
Li
,
Z.
Luo
,
H.
Wakatsuchi
 et al, “
Nonlinear, active, and tunable metasurfaces for advanced electromagnetics applications
,”
IEEE Access
5
,
27439
27452
(
2017
).
10.
F.
Gonçalves
,
A.
Pinto
,
R.
Mesquita
 et al, “
Free-space materials characterization by reflection and transmission measurements using frequency by-frequency and multi-frequency algorithms
,”
Electronics
7
,
260
(
2018
).
11.
Y.
Gao
,
M. T.
Ghasr
,
M.
Nacy
, and
R.
Zoughi
, “
Towards accurate and wideband in vivo measurement of skin dielectric properties
,”
IEEE Trans. Instrum. Meas.
68
(
2
),
512
524
(
2019
).
12.
J.
Baker-Jarvis
,
M. D.
Janezic
, and
D. C.
Degroot
, “
High-frequency dielectric measurements: Part 24 in a series of tutorials on instrumentation and measurement
,”
IEEE Instrum. Meas. Mag.
13
(
2
),
24
31
(
2010
).
13.
L.
Liu
 et al, “
Microwave dielectric properties of carbon nanotube composites
,” in
Carbon Nanotubes
(
Intech Open
,
2010
).
14.
L.
Liu
,
L.
Kong
,
W.-Y.
Yin
, and
S.
Matitsine
, “
Characterization of single- and multi-walled carbon nanotube composites for electromagnetic shielding and tunable applications
,”
IEEE Trans. Electromagn. Compat.
53
,
943
949
(
2011
).
15.
J.
Sheen
, “
Comparisons of microwave dielectric property measurements by transmission/reflection techniques and resonance techniques
,”
Meas. Sci. Technol.
20
,
042001
(
2009
).
16.
C. L.
Gardner
and
G. I.
Costache
, “
The penetration of EM waves through loaded apertures
,”
IEEE Trans. Electromagn. Compat.
37
(
3)
,
358
366
(
1995
).
17.
J. A.
Kong
,
Electromagnetic Wave Theory
(
Wiley-Blackwell
,
2000
).
18.
A. W.
Love
, “
Equivalent circuit for aperture antennas
,”
Electron. Lett.
23
(
13
),
708
710
(
1987
).
19.
Dielectric Resonators
, edited by
D.
Kajfez
and
P.
Guillon
(
Artech House
,
1986
).
20.
C.
Hoecker
 et al, “
The dependence of CNT aerogel synthesis on sulfur-driven catalyst nucleation processes and a critical catalyst particle mass concentration
,”
Sci. Rep.
7
(
1
),
14519
(
2017
).
21.
M. S.
Motta
 et al, “
The role of sulphur in the synthesis of carbon nanotubes by chemical vapour deposition at high temperatures
,”
J. Nanosci. Nanotechnol.
8
,
2442
2449
(
2008
).
22.
D.
Micheli
,
R.
Pastore
,
C.
Apollo
 et al, “
Broadband electromagnetic absorbers using carbon nanostructure-based composites
,”
IEEE Trans. Microwave Theory Tech.
59
,
2633
2646
(
2011
).
23.
P.
Savi
,
M.
Giorcelli
, and
S.
Quaranta
, “
Multi-walled carbon nanotubes composites for microwave absorbing applications
,”
Appl. Sci.
9
,
851
(
2019
).
24.
Z.
Wang
and
G.
Zhao
, “
Microwave absorption properties of carbon nanotubes-epoxy composites in a frequency range of 2–20 GHz
,”
Open J. Compos. Mater.
03
(
2
),
17
23
(
2013
).
25.
A.
Katsounaros
,
K. Z.
Rajab
,
Y.
Hao
 et al, “
Microwave characterization of vertically aligned multiwalled carbon nanotube arrays
,”
Appl. Phys. Lett.
98
,
203105
(
2011
).
26.
M.
Green
and
X.
Chen
, “
Recent progress of nanomaterials for microwave absorption
,”
J. Materiomics
5
(
4
),
503
541
(
2019
).
27.
F.
Hu
,
J.
Song
, and
T.
Kamgaing
, “
Modeling of multilayered media using effective medium theory
,” in
19th Meeting on Electrical Performance of Electronic Packaging and Systems
(
IEEE
,
2010
),
225
228
.
28.
R.
Esquivel-Sirvent
and
G. C.
Schatz
, “
Mixing rules and the Casimir force between composite systems
,”
Phys. Rev. A.
83
,
042512
(
2011
).
29.
F. R.
Zypman
, “
Mathematical expression for the capacitance of coplanar strips
,”
J. Electrost.
101
,
103371
(
2019
).

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