Progress In Electromagnetics Research Symposium Proceedings
2895
Analysis of High Gain Dual Beam Pentagonal Patch Antenna Array
R. Anand1 , Jesmi Alphonsa Jose1 , Anju M. Kaimal1 , and Sreedevi Menon2
1
Amrita Center for Wireless Networks and Applications
Amrita Vishwa Vidyapeetham, Kollam, Kerala, India
2
Department of Electronics and Communication
Amrita Vishwa Vidyapeetham, Kollam, Kerala, India
Abstract— Patch antenna is popular among research community for long range applications
as it radiates in a single direction. But, not much work has been done on patch antenna that
radiates in two directions. Previous works related to dual beam patch antenna require dual
feed and additional circuits for switching. We asked whether is it possible to come up with a
simple geometry for the patch antenna which can produce dual beam with a single feed. In this
paper, we present a high gain, dual beam pentagonal patch antenna as an answer to our research
question. The pentagonal geometry is inspired from a rectangle patch antenna and a triangle
patch antenna. The architecture of the antenna resembles an irregular pentagon comprised of
a triangle placed on top of a rectangle. FEM is used for the analysis of the antenna design.
The pentagonal antenna gave good reflection and radiation characteristics with a 2:1 VSWR
bandwidth of 8.1% at resonant frequency with a peak gain of 5.98 dBi. We further enhanced the
gain of the pentagonal patch antenna using 2 × 1 and 4 × 1 linear pentagonal array configuration
whose peak gains were found to be 8.57 dBi and 9.01 dBi, respectively. Thus, our work highlights a
simple design for dual beam patch antenna which can be applied in areas such as object detection,
RF ablation, MIMO, among others.
1. INTRODUCTION
Patch antenna is gaining much attention due to its low cost and ease in fabrication. The geometry
of the radiating element controls the characteristics of the patch antenna. Various geometries of the
radiating element such as rectangle, circle, triangle, are considered in previous studies [1–3]. The
patch antenna designed for any one of such geometry produces a single directional beam. As there
is a huge demand for dual band operation, patch antenna with dual beam is highly desired. Works
related to dual beam in patch antenna make use of dual feed. Hexagonal shaped patch antenna
with dual feed is proposed in [4]. Even though the hexagonal patch antenna produces dual beam,
the procedure adopted is complex. To the best of our knowledge, a simple geometry for the patch
antenna with dual beam using single feed has not yet proposed.
The pentagonal shaped radiating element for patch antenna design is not explored by many
works. In [5, 7], authors have used pentagonal shape for the radiating patch and ground plane in
the design of coplanar antennas. In [8], we have proposed a pentagonal patch antenna for dual
band applications. In this work, we extend by designing a dual beam pentagonal patch antenna
array. The geometry of the radiating element considered is pentagonal shape, which resembles
triangle placed on top of a rectangle. The shape of the proposed pentagonal patch antenna is
motivated from a rectangular patch antenna and a triangular patch antenna. The characteristics
of the pentagonal patch antenna is initially analyzed. In order to enhance the gain, 2 × 1 and 4 × 1
linear array is formed with the pentagonal structure. The analysis of the pentagonal antenna array
are done using FEM based simulator. The proposed geometries are simple and it doesn’t involve a
complex design and it can produce dual beam without any additional feed.
2. ANTENNA DESIGN
The pentagonal shape of the patch antenna is motivated from a rectangular patch antenna and a
triangular patch antenna. So, we used the characteristics of an inset feed rectangular patch antenna
and an inset feed triangular patch antenna, with resonant frequency at 2.45 GHz, as a reference [1].
The pentagonal geometry is formed with the aid of the two reference antennas. The antenna is fed
with a 50 Ω transmission line.
To enhance the gain of the pentagonal patch, we designed a 2 × 1 and 4 × 1 linear array with
pentagonal elements. The spacing between the array elements and the feeding mechanism were
optimized to achieve maximum gain. The array elements were spaced at a distance of 0.5λ. The
pentagon array was fed by a 50 Ω impedance line. The line was split into two 100 Ω impedance lines
PIERS Proceedings, Prague, Czech Republic, July 6–9, 2015
2896
H
W
L1
L
Y1
w2
w1
w1
(a)
(b)
L2
w3
Y2
w1
(c)
Figure 1: Configuration of (a) single element pentagonal patch antenna, (b) 2 × 1 pentagonal patch antenna
array, (c) 4 × 1 pentagonal patch antenna array.
Table 1: Geometric Parameters of the proposed antennas.
Parameters
Value (in mm)
L
W
H
L1
L2
Y1
Y2
w1
w2
w3
35.97
35.97
35.97
95.9
202.9
30.7
30.7
3.9
0.93
2.1
for each of the elements of the pentagon. The proposed antenna design is as given in Figs. 1(a)–(c)
and the dimensions are provided in Table 1.
The substrate used for all the proposed antenna design is Taconic TLC with relative permittivity εr = 3.2 and a low dielectric loss tangent of 0.003, having a thickness of 1.6 mm. The
proposed geometry is simulated for all the three antennas using Ansoft High Frequency Structural
Simulator(HFSS) and the reflection and radiation characteristics of the antennas are studied.
3. SIMULATION RESULTS
The reflection and radiation characteristics of the proposed antennas are measured using Return
Loss (RL), Voltage Standing Wave Ratio (VSWR), azimuth and elevation pattern Figs. 2(a)–(d).
The RL plots suggests that all the three antennas exhibit good reflection characteristics. The
azimuth pattern suggests the presence of dual beam in all the three proposed antennas. The
characteristics of the pentagonal antennas are summarized in Table 2 for comparison. The peak
gains of all the three pentagonal antennas (5.98 dBi, 8.57 dBi, 9.01 dBi) are better in comparison
Progress In Electromagnetics Research Symposium Proceedings
2897
(a)
(b)
(c)
(d)
Figure 2: Reflection and radiation characteristics of the proposed antennas. The characteristics of the single
pentagonal patch antenna, 2 × 1 pentagonal patch antenna array and 4 × 1 pentagonal patch antenna array
are plotted in continuous line, dashed line and dotted line, respectively. (a) and (b) Reflection characteristics
of the antennas plotted using return loss and VSWR respectively. (c) and (d) Radiation characteristics of
the antenna plotted using Azimuth and Elevation plots respectively.
Table 2: Comparison between the three proposed antennas.
Patch Antenna
Type
Resonant
Frequency (GHz)
Single pentagonal
patch antenna
2 × 1 pentagonal patch
antenna array
4 × 1 pentagonal patch
antenna array
*HPBW of the
Bandwidth (MHz)
Peak Gain (dBi)
HPBW
2.47
21.8
5.98
*40◦ /30◦
2.43
16.5
8.57
*40◦ /30◦
2.39
12.01
9.01
*30◦ /30◦
dual beams are presented with backslash
with the reference triangular antennas (5.41 dBi, 7.17 dBi, 8.32 dBi) but slightly less in comparison
with the rectangular patch antenna (6.62 dBi, 8.97 dBi, 9.97 dBi).
4. DISCUSSION
We have come up with a novel design for dual beam pentagonal patch antenna array. Previous works
on dual beam patch antenna needed dual feed and additional circuits for switching. Works related
to pentagonal or other polygonal patch antenna adopted complex procedure. Since the pentagonal
geometry proposed in this work is formed using a rectangle and a triangle shape, a single feed to the
pentagonal patch makes both rectangular and triangular portion to radiate at the same time, thus
producing beams in two direction. It was also found that the proposed antennas radiate slightly
more in one direction than the other, which also matches with the fact that rectangular patch
antenna radiate more compared to the triangular patch antenna. The proposed pentagonal patch
antennas gives better gain in comparison with triangular patch antenna but has slightly lower gain
compared to rectangular patch antenna. But still these antennas have additional advantage as it
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PIERS Proceedings, Prague, Czech Republic, July 6–9, 2015
radiates in two directions whereas the rectangular patch antenna radiates in only one direction.
In terms of gain enhancement, 2 × 1 linear pentagonal patch arrays was giving appreciable gain
improvement compared to a single pentagonal patch, whereas 4 × 1 linear pentagonal patch array
gave only a slightly better gain when compared to 2 × 1 linear pentagonal patch array, which needs
further investigation on the array geometry. The proposed dual beam pentagonal antennas can
be applied in areas such as object detection, RF ablation, MIMO, among others. Future works
involves validation of simulation results by the network analyzer and exploring various other array
geometries for pentagonal patch antennas.
5. CONCLUSION
In this work, pentagonal patch antenna with good reflection and radiation characteristics is proposed. The pentagonal patch antenna has an advantage of producing dual beam with a single
feed. The gain of the proposed antenna is enhanced using 2 × 1 and 4 × 1 linear pentagonal patch
antenna array. The proposed dual beam pentagonal antennas can be applied in areas such as object
detection, RF ablation, MIMO, among others.
ACKNOWLEDGMENT
We would like to express our immense gratitude to our beloved Chancellor Sri. Mata Amritanandamayi Devi (AMMA) for providing the motivation and inspiration to do this research work. We
also would like to thank Dr. Maneesha V. Ramesh, Director, Amrita Center for Wireless Networks and Applications (Amrita WNA) and Mr. Sethuraman Rao, Professor, Amrita WNA and
colleagues who have willingly helped with their abilities.
This project is partly funded by a grant from Information Technology Research Academy
(ITRA), Department of Electronics and Information technology (DeitY), Govt. of India.
REFERENCES
1. Balanis, C. A., Antenna Theory: Analysis and Design, John Wiley & Sons, Inc., New York,
1997.
2. Garg, R, P. Bhartia, I. Bahl, A. Ittipiboon, Microstrip Antenna Design Handbook, Artech
House, Boston, 2001.
3. Banerjee, S., S. Saha, and S. Sanyal, “Dual band and tri band pentagonal microstrip antenna
for wireless communication systems,” IJESE, Vol. 1, No. 5, Mar. 2013.
4. Basu, S., A. Srivastava, and A. Goswamy, “Dual frequency hexagonal microstrip patch antenna,” IJSRP, Vol. 3, No. 11, Nov. 2013.
5. Jesmi, J., R. Anand, and K. Sreedevi, “Study of coplanar pentagonal antenna,” 10th International Conference on Microwave, Antenna, Propagation and Remote Sensing, ICMARS
Proceedings, 303–306, 2014.
6. Antenna Theory Website, http://www.antenna-theory.com.
7. Jesmi, J., R. Anand, and K. Sreedevi, “A coplanar pentagonal antenna for wireless applications,” 2nd International Conference on Signal Processing and Integrated Networks (SPIN2015), IEEE Proceedings, 303–306, 2015.
8. Dharsandiya, F. and I. Parmar, “Optimization of antenna design for gain enhancement using
array,” IJARCSSE, Vol. 4, No. 1, Jan. 2014.
9. Anand, R., J. Jesmi, M. K. Anju, and K. Sreedevi, “Analysis of dual beam pentagonal patch
antenna,” 2nd International Conference on Computer and Communication Technologies(IC3T2015), accepted.