Elliptical Shape Microstrip Patch Antenna Without Dots

Abstract

This paper introduces the performance of an elliptical shaped antenna with random slots and compares the results between the original patch and the patch without dots. 5.8GHz is the reference or desired frequency set for measuring the performance of this antenna. For the design, three elliptical shaped slots with different dimensions are deployed and connected to each other acting as a main radiating element with coaxial feeding as the excitation method. While, 14 cylindrical dots with different radius are positioned at the left most center of the smallest elliptical slot. An additional slot is created for the coaxial feed point at the center of the radiating patch to allow equal surface current distribution. The antenna is capable of functioning with a maximum directivity of 6.948dBi with a return loss of-22.87dB. Moreover, the proposed antenna radiates in an elliptical polarization pattern where the axial ratio measured is more than 1. The antenna is proficient to be applied in modern communication systems especially point to point communication where it functions at the same bandwidth range.

Full text

Elliptical Shape Microstrip Patch Antenna Without
Dots
V. Priyashman1, M. F. Jamlos1, H. Lago1, M. Jusoh1, Z. A. Ahmad1, M. A. Romli1, M. N. Salimi2
1School of Computer and Communication Engineering, Universiti Malaysia Perlis (UniMAP),
Kampus Pauh Putra, 02600, Arau, Perlis, Malaysia
2School of Bioproses Engineering, Universiti Malaysia Perlis, Kompleks Pusat Pengajian Jejawi 3, 02600 Arau, Perlis, Malaysia
vimal_28@rocketmail.com, faizaljamlos@unimap.edu.my, herwansyahlago@yahoo.com, ame_tango1@yahoo.com,
zahari@unimap.edu.my, asmi@unimap.edu.my, nabil@unimap.edu.my
Abstract-This paper introduces the performance of an elliptical
shaped antenna with random slots and compares the results
between the original patch and the patch without dots. 5.8GHz is
the reference or desired frequency set for measuring the
performance of this antenna. For the design, three elliptical
shaped slots w ith different dimensions are deployed and
connected to each other acting as a main radiating element with
coaxial feeding as the excitation method. While, 14 cylindrical
dots with different radius are positioned at the left most center of
the smallest elliptical slot. An additional slot is created for the
coaxial feed point at the center of the radiating patch to allow
equal surface current distribution. The antenna is capable of
functioning with a maximum directivity of 6.948dBi with a return
loss of -22.87dB. Moreover, the proposed antenna radiates in an
elliptical polarization pattern where the axial ratio measured is
more than 1. The antenna is proficient to be applied in modern
communication systems especially point to point communication
where it functions at the same bandwidth range.
Keywords-elliptical antenna; 5.8GHz antenna;
I. INTRODUCTION
Microstrip antennas are widely used in telecommunications
industry and their applications ranges from mobile and
wireless communications to satellite communications. The
usage of microstrip antennas started to increase in the 1970s
and they became well established as the years went by [1]. For
a microstrip patch antenna, the radiation characteristics are
similar, despite the difference in geometrical shape because
they behave like a dipole [2].
It has been found out that an elliptical shaped microstrip
antenna on a printed circuit board has potential to radiate
circular polarized waves which requires only one feed and the
geometrical design is simple enough to tolerate complex
theoretical analysis to be calculated in standard coordinate
systems [7].
However, discovering the performance and behavior of a
microstrip antenna with random slots is the main purpose of
this paper.
Microstrip antennas are also attractive as they occupy less
space which makes them suitable for arrays [3, 4, 5, 6]. For
this antenna, even with the existence of random and
unsymmetrical slots, the antenna still produces a large
bandwidth of 172.2MHz. As the antenna uses the substrate
FR4, the fabrication is economical [10-31]. Dimension wise,
the antenna has a width of 28.32mm and height of 15.81mm
where it produces the frequency centered at 5.797GHz.
The paper is organized as follows: In Section 2, the
configuration of the antenna will be explained ranging from
the elliptical design, the slots, the cylindrical patches and the
dimensions of the ground plane and FR4 used. The
measurement of the bandwidth, return loss, voltage signal
wave ratio, radiation efficiency and gain is presented in
Section 3. Finally conclusion will be presented at Section 4.
II. ANTENNA DESIGN
The antenna is designed using Computer Simulation
Technology (CST) Microwave Studio 2009. The design has 3
layers consist of ground plane, substrate and the patch.
(a) (b)
(c) (d)
Figure 1. The proposed elliptical antenna (a) Elliptical Patch
(b) Overall layout view (c) Close up view on the dots (d)
Layout of the antenna without dots
From Figure 1(a), a which is the semi major of x-axis is
14.16mm and b which is the semi minor of y-axis is 7.905mm.
Since an ellipse has 2 focus points, the distance from the
center to one of the focus points will be 11.784mm. The first
ba
c
C
y
lindrical slot
Slot 1 Slot 2
2012 IEEE Symposium on Wireless Technology and Applications (ISWTA), September 23-26, 2012, Bandung, Indonesia
978-1-4673-2210-2/12/$31.00 ©2012 IEEE 95

elliptical slot follows the shape of cylinder with an outer
radius of 0.8mm, while the second slot is created using a torus
of outer radius 1.2mm and inner radius 1.1mm. The largest
slot is created using torus of large radius 2.4mm and small
radius 2.28mm. The slots created are separated from each
other and a connector was placed to connect the slots, as
shown in Figure 1(b). Dimension wise, the connector has a
length of 2.5mmm with a width of 0.4mm. The outer radius of
each cylindrical dots from 1-14 is as follows: 0.15mm,
0.12mm, 0.10mm, 0.085mm, 0.085mm, 0.12mm, 0.085mm,
0.085mm, 0.085mm, 0.085mm, 0.12mm, 0.1mm, 0.085mm,
0.085mm, as depicted in Figure 1(c). 0.035mm is the thickness
of the dots. The simulated result of the antenna without the
dots as depicted in Figure 1(d) is presented in section 3.
III. RESULT AND DISCUSS ION
The effects of random and unsymmetrical slots on a
radiating patch produce a startling outcome in terms of return
loss and the bandwidth, as shown in Figure 2. The antenna
operates at a frequency centered at 5.797 GHz with return loss
of -22.87 dB, making its reflected power efficiently low. The
unanticipated end result comes from the bandwidth produced
by the antenna which is high at the value of 172.3 MHz. The
existence of random slots has increased the bandwidth and
also produced low return loss. In depth information on the
effects of slots can be researched in [8].
By removing all the cylindrical dots from the antenna, there
is a trivial shift in frequency drop of the antenna as well as a
minute increment in return loss, which is depicted in Figure
2(a). The antenna produced a higher return loss of -21.624 dB,
with an increment of 1.246 dB. The antenna produces a
bandwidth of 171.6 MHz which is insignificantly lower than
the antenna with cylindrical dots, where it shows a decrement
of only 700 KHz. The disparity between the 2 results can be
pointed to the mutual coupling phenomena that occur between
the dots and the radiating patch and therefore producing better
results in terms of return loss and bandwidth. Furthermore,
mutual coupling in array antennas can be utilize to enhance
bandwidth [9].
Figure 2. Simulated results of S11 and Return Loss for the
Original Radiating Patch and Radiating Patch without dots.
The directivity of an antenna is inversely proportional to the
beam area of an antenna where the smaller the beam area, the
larger the directivity of an antenna. Beam area (ΩA) is given
by the integral of normalized power pattern over a sphere [11].
A more detailed explanation on beam area (ΩA) can be found
in [14].
A noteworthy end product from the existence of random and
unsymmetrical slots is the directivity. A maximum directivity
of 6.948 dBi as depicted in Figure 3(a) reveals that the
proposed antenna is a directional antenna and as explained
before, it must have a smaller beam area.
(a) (b)
Figure 3. Simulated results of original antenna with the
antenna without dots (a) Directivity of Original Antenna (b)
Directivity of Original Antenna without dots
The subtraction of cylindrical dots produces a lower angular
beamwidth of 126.3° and a directivity of 6.853 dBi, a reflux of
0.095dBi, as shown in Figure 3(b). The result explains that the
dots only have mild effect on the directivity of the antenna.
The Table 1 below are the summarized results of this paper.
Table 1. Comparison of results between the original patch and
the patch without the dots
IV. CONCLUSION
The performance of an elliptical shaped microstrip patch
antenna with random and unsymmetrical slots is presented in
this paper. This design shows the effects of the random slots,
cylindrical patches and connector which radically influence
the performance of the radiating patch. The presence of slots
and connector is to be credited for the capability of the
antenna to be able to produce a maximum directivity of 6.948
dBi and large bandwidth. The antenna which has a dimension
of semi major axis of 14.16mm which is the width and semi
minor axis of 7.905mm which is the height of the antenna is
tunable to further improve the gain and efficiency. The
conclusion that can be derived here is that even with aimless
Parameters
Original Antenna
Patch
Antenna
without dots
Simulation Simulation
Bandwidth (MHz) 172. 3 171.6
Return Loss (dB) -22.87 -21.624
VSWR 1.1548 1.1809
Directivity (dBi) 6.948 6.853
2012 IEEE Symposium on Wireless Technology and Applications (ISWTA), September 23-26, 2012, Bandung, Indonesia
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positioning of slots, the microstrip patch can still be tuned and
made applicable for modern communication systems.
REFERENCES
[1] Wonkyu Choi, Yong Heui Cho, Cheol-Sik Pyo, and Jae-Ick Choi “A
High Gain Microstrip Patch Array Antenna Using a Superstrate Layer”,
ETRI Journal, Volume 25, Number 5, pp. 407-411, 2003.
[2] R. Garg, P. Bhartia, I. Bahl and A. Ittipiboon, Microstrip antenna design
Handbook, Artech House, Norwood, MA, 2000.
[3] N. K. Uzunoglu, N. G. Alexopoulos, and J. G. Fikioris, “Radiation
Properties of Microstrip Dipoles,” IEEE Trans. Antennas
Propagat.,Vol.AP-27, No. 6, pp. 853–858, 1979.
[4] I. E. Rana and N. G. Alexopoulos, “Current Distribution and Input
Impedance of Printed Dipoles,” IEEE Trans. Antennas Propagat.,
Vol.AP-29, No. 1, pp. 99–105, 1981.
[5] P. B. Katehi and N. G. Alexopoulos, “On the Modeling of
Electromagnetically Coupled Microstrip Antennas-The Printed Strip
Dipole,” IEEE Trans. Antennas Propagat., Vol. AP-32, No. 11, pp.
1179–1186, 1984.
[6] D. M. Pozar, “Analysis of Finite Phased Arrays of Printed Dipoles,”
IEEE Trans. Antennas Propagat., Vol. AP-33, No. 10, pp. 1045–1053,
1985.
[7] Liang C. Shen, “The Elliptical Microstrip Antenna with Circular
Polarization”, IEEE Transactions On Antennas And Propagation,
Vol.AP-29, No.1, 1981.
[8] V. Sharma, V.K. Saxena, K.B. Sharma, J.S. Saini and D. Bhatnagar
“Probe Feed Elliptical Patch Antenna with Slits for WLAN
Application”, Proceedings of International Conference on Microwave,
pp. 901-903, 2008.
[9] M. Wang, W. Wu and Z. Shen, “Bandwidth Enhancement of Antenna
Arrays Utilizing Mutual Coupling between antenna Elements”,
International Journal of Antennas and Propagation, Vol. 2010, 10 pages,
2010.
[10] M.F. Ja mlos, O.A. Aziz, T.A. Rahman, M.R. Kamarudin and P. Saad,
“Reconfigurable Radial Line Slot Array (RLSA) Antenna for Beam
Shape And Broad-Side Application”, J. of Electromagn. Waves and
Appl., Vol.24, pp. 1171-1182, 2010.
[11] J.D. Kraus and R.J. Marhefka, Antennas For All Applications Third
Edition, McGraw Hill, Singapore, International Edition 2003.
[12] M. F. Jamlos, M. R. Kamarudin, M.A. Jamlos and M. Jusoh, “ A novel
reconfigurable quadratic antenna for wimax and 4G systems”
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Pages:
416–421, Volume 54, Issue 2, February 2012
[13] M. Jusoh, M. F. Jamlos and M. R. Kamarudin, A compact dual bevel
planar monopole antenna with lumped element for ultra high
frequency/very high frequency application”, MICROWAVE AND
OPTICAL TECHNOLOGY LETTE RS, Pages: 156–160Volume 54,
Issue 1, January 2012
[14] M. Jusoh, M. F. Jamlos, M. R. B. Kamarudin, and M. F. b. A. Malek, "A
MIMO antenna design challenges for UWB application," Progress In
Electromagnetics Research B, Vol. 36, 357-371, 2012.
[15] M. Jusoh, M. F. Jamlos, M. R. Kamarudin, F. Malek, M. H. Mat, and M.
A. Jamlos, “A Nov el Compact Tree-Design Ant enna (NCTA) wit h High
Gain Enhancement for UWB Application”, J. of Electromagn. Waves
and Appl., Vol. 25, 2474–2486, 2011
[16] M. F.Jamlos, O. A. Aziz, T. A. Rahman and M. R. Kamarudin “A
Reconfigurable Radial Line Slot Array (Rlsa) Antenna For Beam Shape
And Broad Side Application” J. of Electromagn. Waves and Appl., Vol.
24, 1171– 1182, 2010
[17] M. F. Jamlos, T. A. Rahman, and M. R. Kamarudin, “A Novel Adaptive
Wi-Fi System With Rfid Technology”, Progress In Electromagnetics
Research, Vol. 108, 417-432, 2010
[18] M. F. Jamlos, O. A. Aziz, T. A. Rahman and M. R. Kamarudin “A beam
steering radial line slot array (rlsa) antenna with reconfigurable
operating frequency”, J. of Electromagn. Waves and Appl., Vol. 24,
1079–1088, 2010
[19] M. F. Jamlos, T. A. Rahman, and M. R. Kamarudin, “Adaptive Beam
Steering Of Rlsa Antennawith Rfid Technology”,Progress In
Electromagnetics Research, Vol. 108, 65-80, 2010.
[20] M.Jusoh, M.F.Jamlos, M.R. Kamarudin, Z.A.Ahmad, M.A.Romli “ A
Dual Bevel Compact Planar Monopole Antenna for UHF Application”
Progress In Electromagnetics Research Symposium, 2012
[21] M.Jusoh, M.F.Jamlos, M.R. Kamarudin, Z.A.Ahmad, M.A.Romli “A
UWB MIMO Spatial Design Effect on Radiation Pattern” Progress In
Electromagnetics Research Symposium, 2012
[22] M.Jusoh, M.F.Jamlos, M.R. Kamarudin “A UWB MIMO Spatial
Design Effect on Radiation Pattern” IEEE International Rf And
Microwave Conference, 2011
[23] Mohd Faizal Jamlos, Muhammad Ramlee kamarudin, Mohd Fareq
Malek, Mohd Aminudin Jamlos, Muzammil Jusoh, Zahari Awang
Ahmad, and Abdul Hafiizh Ismail “A Beam Shaping Reconfigurable
Radial Line Slot Array(RLSA) Antenna” International Symposium on
Antennas and Propagation (ISAP), 2011
[24] Ezla Najwa Ahyat, Nurhidayah Ramli, Muhammad Ramlee Kamarudin,
Tharek Abd Rahman and Mohd Faizal Jamlos “A Novel Pattern
Reconfigurable Dipole-Yagi Antenna for Wireless Body Area Network
(WBAN) Applications, International Symposium on Antennas and
Propagation (ISAP)”, 2011
[25] Muzammil Jusoh, Faizal Jamlos and Ramlee Kamarudin “Configuration
Study and Analysis of UWB MIMO Antenna Performance”,
International Symposium on Antennas and Propagation (ISAP), 2011
[26] M.F.Jamlos, M.Jusoh, M.F. M alek, M .A.Jamlos, Z.A.Ahmad, A.H.
Ismail, M.R.Kamarudin and M.H.Muslim, “A unique Reconfigurable
Slot Array Antenna for WiMAX Application” IEEE-APS Topical
Conference on Antennas and Propagation in Wireless Communications,
2011
[27] M.Jusoh, M.F.Jamlos, M.R. Kamarudin, M.F. Malek, E.I. Azmi “A
Compact Size Antenna with High Gain Enhancement for IEEE
802.15.3”, IEEE Symposium on Wireless Technology Application 2011
[28] M.S. Zulkefli, F. Malek, M.F.jamlos “Novel Dual-Oval Shape Antenna
With Bandstop Characteristic For Uwb Application”, IEEE Symposium
on Wireless Technology Application 2011
[29] M. F. Jamlos, T. A. Rahman, M. R. Kamarudin, M. T. Ali, M. N. Md
Tan, and P. Saad “Reconfigurable Aperture Coupled Planar Antenna
Array at 2.3 GHz”, Progress In Electromagnetics Research Symposium
Proceedings, Xi'an, China, March 22-26, 2010
[30] M. F. Jamlos, T. A. Rahman, M. R. Kamarudin, M. T. Ali, M. N. Md
Tan, and P. Saad “The Gain Effects of Air Gap Quad ratic Aperture-
coupled Microstrip Antenna Array” PIERS Proceedings, Cambridge,
USA, July 5-8, 2010
[31] M. F. Jamlos, T. A. Rahman, M. R. Kamarudin, M. T. Ali, M. N. Md
Tan, and P. Saad “Integration of Rfid technology into reconfigurable
Aperture coupled patch array (racpa) antenna system” European
Conference on Antennas and Propagation 2010, 12-16 April 2010,
Barcelona.
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