Graphene Based Textile Antennas for Integrated and
Wearable Applications
1
Isidoro Ibanez Labiano,
1
Syeda Fizzah Jilani,
2
Muhammed Said Ergoktas,
2
Coskun Kocabas,
3
Elif Ozden-Yenigun,
1
Akram Alomainy
1
School of Electronic Engineering and Computer Science, Queen Mary University of London, United Kingdom
2
School of Materials, Materials Engineering, University of Manchester, United Kingdom
3
School of Design, Textiles, Royal College of Art, London, United Kingdom
{i.ibanezlabiano, a.alomainy}@qmul.ac.uk, elif.ozden-yenigun@rca.ac.uk
Abstract—This paper presents an antenna designed to achieve
wideband by using graphene as a conductive patch. In order to
provide flexibility, the cotton fabric is used as a substrate. The
proposed antenna covers a bandwidth of 2–8 GHz. Simulated
antenna efficiency is approximately 60% in overall bandwidth.
The attractive features of conformity, lower design complexity and
fabrication ease as well as integration of an environment friendly
and low cost graphene have suggested the proposed antenna well-
suited for body-centric, biomedical and wearable applications.
Keywords—antenna; graphene; textile; wearable; wireless.
I. I
NTRODUCTION
Wireless technology has experienced notable advancement
in the past decade in mobile communication networks and user-
friendly applications [1]. The ever-growing number of wireless
devices and especially body-centric gadgets has motivated the
research to focus on the utilization of new materials. Among the
choices of recent materials, graphene is extensively highlighted
due to its unique features and eco-friendly nature [2]. Graphene
is a two-dimensional carbon crystal with remarkable electrical
conductivity to allow propagation of high-frequency signals [3].
In wireless devices, antenna is regarded as a core module and in
order to realise graphene based radio-frequency (RF) circuitries,
intensive efforts have been made in the design, implementation
and performance evaluation of the graphene antennas [4-6].
Patch antennas have the advantage of planar integrations,
however, for the wearable and body-centric applications, the
conformity of the antenna is highly desirable, which can only be
realized by flexible substrate. Textile based antennas are capable
to provide an ease of integration in wearable electronics. Several
methods of fabrication, such as, inkjet printing, screen printing,
conductive embroidering, or by adhesive conductive fabric
patterning, are developed for the implementation of textile
antennas [7]. The research suggests a graphene based antenna
on a textile substrate as a potential candidate for smart textiles
and state-of-the-art body-centric systems.
II. A
NTENNA
D
ESIGN AND
F
ABRICATION
A. Antenna Design and Numerical Modelling
The designed antenna consists of a coplanar-waveguide (CPW)-
fed planar inverted cone shaped patch geometry [9], where the
optimised dimensions (in mm) are as shown in Fig. 1 (a). Two
layers of different substrates are used, i.e. thin sheet of micro-
glass fiber and a cotton textile. The graphene patch is designed
on a micro glass-fiber (thickness = 1.5 mm, dielectric constant
= 5) which is backed with a cotton fabric to provide additional
support, lowers the value of effective permittivity and increases
the thickness and robustness of the prototype.
B. Synthesis of Multilayer Graphene and Transfer Printing of
Graphene on Polyethylene Sheets
Multilayer graphene samples were synthesized on 50 μm
thick nickel foils using chemical vapor deposition system. The
thickness of ML graphene samples were controlled by the
growth temperatures varied between 900–1000 °C. The number
of graphene layers was approx. 100. Transfer printing of large
area ML-graphene on a 20 μm thick porous polyethylene (PE)
substrate was conducted. Porous PE sheet was immersed into
liquid for conformal coating of ML graphene, and then dried in
an oven at 70 °C for 2 hours to remove residual water molecules.
The sheet resistance of ML-graphene was c.a 25 Ω/sq.
C. Fabrication of Graphene Based Textile Antenna
The ML-graphene sheets were laminated with insulating
glass microfibers nonwoven supplied from Pilkington Co. to
avoid possible short-circuiting effect of crinkled graphene edges
touching fabric. The graphene sheet was cut and transferred onto
micro glass-fiber by heat lamination as in Fig. 1 (b). This method
triggered by applied heat assists bonding between the two sheets
provides strong interface. Adhesive copper tape was placed on
top for CPW ground. The structure is then backed with a fabric.
III. P
ERFORMANCE
E
VALUATION OF THE
A
NTENNA
The antenna performance is evaluated by parametric
analysis and investigation of results of S-parameters, radiation
pattern, realized gain and efficiency. The results obtained in
numerical estimation and testing of the fabricated prototype
shows a good agreement. Though some mismatches are
observed due to fabrication tolerances or real-time losses during
testing which have not be accommodated in simulation. Fig. 2
shows that the simulation cover complete 2–8 GHz band, while
the measurements taken from the Vector Network Analyser
(VNA) illustrate a bandwidth of 2.45–8 GHz.
(a) (b)
Fig. 1. The proposed graphene based antenna (a) simulated model with
optimised dimensions in mm; (b) fabricated model.
Fig. 2. Simulated and measured S
11
of the proposed graphene based antenna.
The radiation patterns of the antenna are shown in Fig. 3 for
both E and H-plane cuts. The magnitudes are normalized with
the value of peak gain of 2.83 dBi. The plots shows a fairly
consistent omnidirectional radiation pattern. Fig. 4 shows the
simulated efficiency vs. frequency of the proposed antenna. The
total efficiency of the designed antenna computed in CST
simulation is ~60% in the desired range of operation, which is
significantly good for textile based antennas.
(a) (b)
Fig. 3. The radiation pattern of the proposed graphene based antenna.; (a) E-
plane cut, at φ = 90˚, (b) H-plane cut, at φ = 0˚.
Fig. 4. Simulated antenna efficiency of the proposed graphene based antenna.
IV. C
ONCLUSION
This paper has presented a graphene based antenna which is
designed and implemented on a flexible textile substrate to
achieve desired level of conformity. The antenna has attained an
impedance bandwidth of 6 GHz ranging from 2–8 GHz. The
omnidirectional radiation has been observed due to co-planar
structure. The simulated results has shown that the realized gain
of the antenna ~3 dBi with the antenna efficiency of ~60 %. The
designed antenna has potential in advanced materials devices,
especially in the conformal biomedical applications.
A
CKNOWLEDGMENT
This project has received funding from the European Union’s
Horizon 2020 research and innovation programme under grant
agreement No 796640. This research was supported by the
School of EECS, Queen Mary University of London.
R
EFERENCES
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(dB)
Efficiency (%)
