Electromagnetic heating effect of graphene absorber
Wei Qi Lv
State Key Laboratory of Millimeter Waves, Southeast
School of Information Science and Engineering, Southeast
University
Nanjing, China
363672703@qq.com
Abstract—In this work, a narrowband and a broadband
graphene-based absorber models are established to analyze
theirs thermal effects by using COMSOL software. Exciting by
high-frequency electromagnetic (EM) waves, the graphene-based
absorber will have a thermal effect, due to the energy transform
from EM to thermal, which results in an increase of temperature
of the absorber. Thermal profiles of narrowband and broadband
graphene absorber verified by infrared camera testing have good
agreement with the simulated results.
Keywords—Graphene;
distribution map
frequency
selective
surface;
heat
Wei Bing Lu*
State Key Laboratory of Millimeter Waves
School of Information Science and Engineering,Southeast
University
Nanjing, China
wblu@seu.edu.con
of absorbers use FR4 dielectric sheet as substrate, its relative
dielectric constant is 4.4. As shown in Fig.1, purple part is the
graphene layer, and gray part is the substrate. The back of the
substrate is a perfect electrical conductor.The thickness of
narrowband absorber is 3mm and the thickness of broadband
absorber is 2mm. As shown in Fig.1a, the unit cell dimensions
of narrowband absorber are D = 9mm and d = 2mm. The unit
period is p = 10 mm. As shown in Fig.1b, ,the dimensions of
broadband absorber unit are D = 5mm, d=3.5mm p = 13 mm
and L = 1.5mm. The Power of the applied electromagnetic
wave is 0.1 W.
I. INTRODUCTION
In the past few decades, absorbers have been widely used
in civil and military applications, such as used for radars
absorption [1]. In order to improve the performance of the
absorber, frequency selective surfaces (FSS) [2] can be used in
combination with absorber. Recently, graphene-based
absorbers have received extensive attention. Graphene is a
two-dimensional material of one layer of carbon atoms and has
very good electrical and thermal conductivity at room
temperature. Its good tunable properties have been verified in
the terahertz and microwave bands. Most of the current
research on graphene absorbers is mainly focus on the
electromagnetic properties of graphene [3] or the thermal
management of graphene in electronic devices [4]. However,
little research has been done on the EM heating effect of
graphene related devices.
(a)
(b)
Fig. 1. (a) Geometric model of narrowband absorber (b) Geometric model of
broadband absorber
Narrowband absorber simulation results are shown in Fig.
2. The frequency of the incident wave is 13.2 GHz. In order to
analyze the heating effect, different sheet resistance of
graphene in narrowband absorber are simulate. These sheet
resistances are 5Ω/sq, 40Ω/sq, 80Ω/sq, 200Ω/sq.
In this paper, we use COMSOL software to simulate the
EM heating effect of two different types of graphene absorbers,
namely a narrowband adjustable absorber and a broadband
absorber. Finally the infrared thermal image is used to shoot
the heat distribution diagram of these two types of absorbers.
The structure of this paper is as follows. In section II, the
basic structure of two types of absorbers is established[2]. The
simulation results are also obtained. In section III, the
experimental setup and experimental results are given. Finally,
we give a summary of this paper in section IV.
(a)
(b)
(c)
(d)
II. ELECTROMAGNETIC HEATING EFFECT SIMULATION OF
ABSORBER
The models of the two types of absorber established in
COMSOL are shown in Fig. 1. This paper uses floquet
periodic boundary conditions in the simulation. Both two types
Fig. 2. Heat distribution map of different square narrowband absorbers (a) 5
Ω/sq (b) 40Ω/sq (c) 80Ω/sq (d) 200Ω/sq
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Similarly, we choose different sheet resistance of graphene
in broadband absorber to simulate the heating effect. These
square resistances are 5 Ω/sq, 20 Ω/sq, 50 Ω/sq, 70 Ω/sq.
The applied electromagnetic wave frequency is 13.2 GHz.The
result of the simulation is shown in Fig. 3.
(a)
First, we measure the heat distribution of narrowband absorber.
In order to compare the effects of different sheet resistance of
graphene, we put the narrowband absorbers with two sheet
resistance of graphene together for imaging the heat
distribution, on the left is 40 Ω/sq, and the right is 5 Ω/sq. The
specific placement method and measurement results are shown
in Fig. 6.
(b)
(b)
Fig. 6. (a) narrowband graphene absorber placement method (b) Thermal
imaging camera measurement results
(c)
Similarly, we measure the heat distribution of broadband
absorber with square resistance of graphene 20 Ω/sq and 70
Ω/ sq . The measurement results of the infrared camera and
placement method are shown in Fig. 7.
(d)
Fig. 3. Heat distribution map of different sheet broadband absorbers (a) 5 Ω
/sq (b) 20 Ω/sq (c) 50 Ω/sq (d) 70 Ω/sq
It can be seen from the simulated results that in the
excitation of 13.2 GHz electromagnetic wave, The absorber
produces a thermal effect. The heating effect is due to the
conversion from electromagnetic energy to heat energy. Refer
to the microwave absorption rate for absorbers with different
sheet resistances of graphene in Ref [3]. From the figure， It
can be observed that the absorbers with different sheet
resistances have different absorbing rates. Therefore, the heat
distribution of the devices are different. The relationship
between the absorbing rate and the frequency is shown in
Figure 4.
(b)
(b)
Fig. 4. Absorption coefficients of the narrow absorber (b) Absorption
coefficients of the broadband absorber
(b)
Fig. 7. (a) broadband graphene absorber placement method (b)Thermal
imaging camera measurement results
According to the experimental results, it was confirmed
that graphene was heated when receiving high frequency
microwaves energy and transforming it into thermal energy. In
Figure 4, it can be found that different square sheet absorber
have different absorbing rate. Simulations and experiments
have confirmed that the absorbers with different absorbing
rates have different heat distribution map.
IV. CONCLUSIONS
In this paper, we simulated the electromagnetic heating
effect of two different absorbers. Through the simulation of
COMSOL software, we obtained the heat distribution diagram
of the graphene-based absorber with different resistance.
Finally, the heat distribution diagram of the absorber was
taken using an infrared camera.
REFERENCES
III. EXPERIMENT
The method of measuring the heat distribution of
graphene-based absorbers is to use infrared camera, flir T250,
and a free space microwave device, as shown in Fig. 5.
[1]
[2]
[3]
[4]
(a)
(b)
L. J. Du Toit, “ The design of Jauman absorbers, ” IEEE Antennas
Propag. Mag., vol. 36, no. 6, pp. 17–25, 1994.
PD. Yi, X.-C. Wei, and Y.-L. Xu, “Tunable Microwave Absorber Based
on Patterned Graphene, ” IEEE Trans. Microw. Theory Techn， vol6.
no .8, pp. 2819-2826, Aug. 2017.
Hao Chen, ,Wei-Bing Lu. Zhen-Guo Liu, “Experimental Demonstration
of Microwave Absorber Using Large-Area Multilayer Graphene-Based
Frequency Selective Surface,” in IEEE on Microwave and TechniQues,
vol. 66, No.8 , pp. 3807–3816, Aug. 2018
Zhong Yan, Guanxiong Liu, Javed M. Khan, “ Graphene quilts for
thermal management of high-power GaN transistors, ” nature
communications, vol. 3, no. 827, pp. 1-8, May. 2012.
Fig. 5. (a) Free space microwave device (b) infrared camera flir T250
Authorized licensed use limited to: Auckland University of Technology. Downloaded on June 07,2020 at 22:52:49 UTC from IEEE Xplore. Restrictions apply.