The 12th International Conference on Science, Technology
and Innovation for Sustainable Well-Being (STISWB XII),
27-29 April 2020, Tsukuba Ibaraki, Japan
…………………………………………………………………………………………………….............................................................................
ETE-093
The 4G Monopole Antenna Design
for Vehicular Wireless Communication
Charinsak S.1* Adirek J.1, Chawangsak T. 1 and Suwit P. 1
1
Department of Electronics and Telecommunication Engineering, Rajamangala University of
Technology Isan, Khon Kaen Campus, Khon Kaen, Thailand.,
*Corresponding Author: charinsak.sa@rmuti.ac.th
Abstract
This paper presents the design of the triangular monopole antenna on a perpendicular
small ground plane for 4G applications at 1800MHz and 2100MHz. The main objectives of this
research were to design and analyze the performance of the proposed antenna improved with a
double-step micro-strip feed. The parameters used in the analysis rely on resonance frequency
that was obtained by the reflection coefficient from the simulation results. The antenna
prototypes have been built and measured to verify the simulation results. The impedance
bandwidth of prototype antenna was measured with a value of 1809MHz to 2327MHz which
was changed to a higher frequency band when compared to the result of simulation (1752MHz to
2118MHz) but can still cover the range of both operating frequencies. The maximum gain from
simulation and measurement was 2.91dB and 2.55dB for 1800MHz, 3.97dB and 3.12dB for
2100MHz, respectively. Finally, the radiation pattern was conducted and confirmed by
measurement results.
Keywords: triangular monopole antenna, double-step micro-strip feed.
1. Introduction
With the rapid growth of vehicular
wireless communication, modern vehicles
are equipped with various types of wireless
communication equipment, such as FM
radio, mobile phone, navigation system, etc.
At the same time, for the suitability and
compactness, the antenna under the sharkfin housing becomes more popular in
commercial vehicle. However, due to the
limited space within the shark-fin housing,
the integrated antenna design, especially the
4G antenna, is very important for car
manufacturers.
Recently, several promising antennas for
automotive applications have been proposed
[1]-[2]. In [1], a monopole antenna
operating in two bands of 824–960 MHz
and 1710–2690 MHz is presented. Also, the
antennas in [2] were large to fit in shark-fin
housing. Some antennas of the small device
were made from flexible material which is
suitable for designing to including in a small
housing [3-5] was reported. In this paper, a
fully integrated triangular monopole antenna
to be used with 4G applications is proposed.
In order to be able to mount the antenna
into a shark-fin box that can be mounted on
a vehicle and still have the antenna
performance as desired, some techniques
have been used, such as the modify
grounded and multiple matching microstrip
elements.
This paper proposes a compact and low
cost triangular monopole antenna on a
perpendicular small ground for 4G
automotive applications at 1800MHz and
The 12th International Conference on Science, Technology
and Innovation for Sustainable Well-Being (STISWB XII),
27-29 April 2020, Tsukuba Ibaraki, Japan
……………………………………………………………………………………………………......................................................................
.......
2100MHz. The antenna utilized for the
receiver of 4G device for accommodating
antennas into shark-fin housing is
compatible to install on roof-top of vehicle.
The paper was divided into four sections
as follows. The first section is the
introduction of antenna design and the
background of this study. The second
section is the prototype design along with
discussion on antenna optimization. Then,
the test result of prototype was shown. The
last section is conclusion.
2. Antenna Design
The antenna’ s dimensions were
determined and calculated using basic
triangular patch antenna [6] for center
frequency f r  1800MHz , FR-4 dielectric
substrate thickness ( TS ) was 1. 6 mm. and
dielectric constant (  r ) was 4.5;
A

2c

3 fr  r
where c was a speed of light
 r was a relative dielectric constant.
Finally, the other size such as a
perpendicular ground plane used the
optimize result from the simulation. The
first version of a triangular monopole
antenna with single-step micro-strip feed
antenna model was shown in Fig. 1.
Fig. 1 a triangular monopole antenna
with single-step micro-strip feed antenna
model.
However, the single-step of feed line
was not enough bandwidth to cover the
required frequency band. So, we adapt a
double-step feed line into the model as
shown in Fig.2 and optimize the design
again.
Next, the width of micro-strip
transmission feed line ( W ) can be
calculated from

W  (exp H )
1



TS 
8
4 exp H  
1
(2)
where
Z 0 2( r  1)
119.9
1    1   1 4 
  r
 ln  ln 
2   r  1  2  r  
H 
(3)
Then, the length of matching
transformer that was a quarter wavelengths
was calculated from
L


g
0

4
4 
eff
(4)
a) Front view
b) Bottom View
Fig. 2 Triangular monopole antenna with
double step feed antenna model.
The result of each dimension of model
after the optimize result from the simulation
was described in a Table 1. The result of
S11 in Fig.3 shown that, the improved
antenna bandwidth is equal to 1752MHz to
2118MHz.
The 12th International Conference on Science, Technology
and Innovation for Sustainable Well-Being (STISWB XII),
27-29 April 2020, Tsukuba Ibaraki, Japan
……………………………………………………………………………………………………......................................................................
.......
Table 1. The dimension of triangular
monopole antenna with double
step feed.
Dimension
Paramenters
Value
(mm.)
Dimension
Paramenters
Value
(mm.)
S1
L1
L5
W1
61.5
10
10
8.5
W5
L11
L
X
10
12
90
50
Fig. 3 a S11 result of triangular
monopole antenna with double-step microstrip feed antenna model from simulation.
of proposed antenna was 2.91dB and 3.97dB
for 1800MHz and 2100MHz, respectively.
3. Measurement Results
After completing the result of the
antenna simulation, the measurement was
conducted by an E5063A network analyzer.
The completed prototype antenna was
fabricated and illustrated in Fig. 6.
a) Front view
b) Bottom View
Fig. 6 Prototype of proposed antenna.
The values of return loss (S11), obtained
from the measurement results of the
prototype antenna, was shown in Fig. 7.
Then, a radiation pattern from measurement
was shown in Fig. 8-9.
Fig. 4 the 3D radiation pattern at
1800MHz of triangular monopole antenna
with double step feed.
Fig. 7 S11
measurement.
results
from
prototype
Simulation
Measurement
Fig. 5 the 3D radiation pattern at
2100MHz of triangular monopole antenna
with double step feed.
Fig 4 and 5 showed that the simulation
results of 3D radiation pattern and the gain
Simulation
Measurement
a)XZ Plan
b) XY Plan
Fig. 8 the radiation pattern of triangular
monopole antenna with double-step feed at
1800MHz.
The 12th International Conference on Science, Technology
and Innovation for Sustainable Well-Being (STISWB XII),
27-29 April 2020, Tsukuba Ibaraki, Japan
……………………………………………………………………………………………………......................................................................
.......
and attractive for applying in vehicular
wireless communication.
Simulation
Measurement
Simulation
Measurement
a)XZ Plan
b) XY Plan
Fig. 9 the radiation pattern of triangular
monopole antenna with double-step feed at
2100MHz.
According to the measurement results,
the antenna gain of prototype antenna was
2.55dB for 1800MHz and 3.12dB for
2100MHz. In addition, the value of the
impedance bandwidth was from 1809MHz
to 2327MHz. Finally, the radiation pattern
of triangular monopole antenna on a
perpendicular small ground plane was tested
and comfirmed by the measurement results
of prototype antenna.
4. Conclusion
This research focuses on designing the
dual-frequency antenna by using a
triangular monopole antenna combined to a
basic perpendicular small ground plane and
a double-step micro-strip feed. The small
rectangular planar was used as the ground
plane with a triangular monopole antenna. It
also facilitated the fabrication of an antenna
with low cost FR4 materials to be suitable
for being used with shark-fin housing which
was compatible to be installed on roof-top
of the vehicle. The simulation result showed
that the bandwidth increased when antenna
was used with double-step microstrip feed.
The measured bandwidth was slightly
changed because of the effect of
measurement environment. It also shifted
the measured result of bandwidth dropping
the maximum gain of the antenna’ s
prototype when comparing with the results
from a simulation. However, the maximum
gain of the prototype antenna was still
greater than 2.5dB, both frequency bands
5. Acknowledgments
The author would like to thank Mr. Jaruk
Wutthisen and Mr.Yossak Trinarong for
kindly help with antenna measurement
results. Finally, the author would also thank
the Faculty of Engineering, Rajamangala
University of Technology Isan, Khon Kaen
Campus, for financial support. (Contract No.
ENG04/63).
7. References
[1] M. Cerretelli, V. Tesi, and G. B.
Gentili, “Design of a shape-constrained
dual-band polygonal monopole for car roof
mounting,” IEEE Trans. Veh. Technol., vol.
57, no. 3, pp. 1398–1403, May 2008.
[2] A.Michel, P. Nepa,M.Gallo, I.Moro,
andA. P. Filisan, “Printed wideband antenna
for LTE-band automotive applications,”
IEEE Antennas Wireless Propag. Lett., vol.
16, pp. 1245–1248, 2017.
[3] C. Saetiaw, S. Summart and C.
Thongsopa, "Curved Double-layer Strip
Folded Dipole Antenna for WLAN
Applications," in 5th International Electrical
Engineering
Congress
(iEECon2017),
Pattaya, 2017, pp. 454-458.
[4] C. Saetiaw, "Design of flexible
triple-layer folded dipole antenna on curved
surface for WLAN," 2017 8th International
Conference
of
Information
and
Communication Technology for Embedded
Systems (IC-ICTES), Chonburi, Thailand,
2017, pp. 1-4.
[5] C. Saetiaw and C. Thongsopa,
"Multilayer Strip Dipole Antenna Using
Stacking Technique and Its Application for
Curved Surface" International Journal of
Antennas and Propagation,vol.2013, pp.110 , 2013.
[6] Rajesh K Vishwakarma, J A Ansari,
M K Meshram, "Equilateral triangular
microstrip antenna for circular polarization
dual band operation ", Indian Journal of
Radio & Space Physics.