International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 3, Issue 6, June 2014
ISSN 2319 - 4847
Double E-shaped Multiband Fractal Microstrip
Patch Antenna for Wireless Applications
1
Vijeta Attri 2Mr. Vishal Dora and 3Dr. Rajesh Goel
1
MTech Student, Samalkha Group of Institutions, Samalkha
Assistant Professor, Samalkha Group of Institutions, Samalkha
3
Professor, Samalkha Group of Institutions, Samalkha
2
Abstract
In this Paper, design and implementation of multiband fractal patch antenna has been carried out. In order to make E-shaped
fractal patch antenna, slots have been cut on both sides of patch to form double E-shaped fractal patch antenna. Further slots
have been also cut on ground to make plus shape DGS. As result multiband fractal patch antenna with defected ground structure
is obtained. By applying fractal geometry and DGS, antenna resonates at four bands 5.1 GHz, 7.8 GHz, 8.7 GHz and 9.6 GHz
with good bandwidth and gain. This antenna had gain of 4.07 dBi, 4.41 dBi, 7.28 dBi and 7.33 dBi together with bandwidth of 615
MHz, 480 MHz, 640 MHz and 600 MHz at corresponding frequencies. Design and simulation has been carried out using IE3D
simulation software. This antenna found its application for WLAN (wireless local area network), C band and X band applications.
Keywords: Microstrip, Fractal, Multiband, WLAN.
1. INTRODUCTION
In the current scenario developments in wireless communication industries continue to derive requirement of small,
compatible and affordable microstrip patch antennas. It is required to have antenna that can be useful for many
applications and has small size. A patch antenna is a narrowband antenna with large beam width. It is fabricated by
etching the antenna element pattern in metal trace which is bonded to an insulating dielectric substrate such as a printed
circuit board with a continuous metal layer bonded to the opposite side of the substrate known as a ground plane. There
are different shapes of microstrip antenna which are square, rectangular, circular and elliptical, but antenna can have any
continuous shape. Instead of using a dielectric substrate, some antennas can be made of a metal patch mounted above a
ground plane using dielectric spacers. Microstrip antennas are best choice for wireless devices because of characteristics
like low profile, low weight, ease of fabrication and low cost. Since it is common practice to combine several radios into
one wireless and use single antenna. Microstrip antenna suffers from disadvantages like they have less bandwidth and
gain. For obtaining multiband and wideband characteristics, different techniques have been used like cutting slot in patch,
fractal geometry and DGS. In order to increase bandwidth DGS has been used. DGS may be realized by cutting shape
from ground plane. Shape can be simple or complex.Whenever different cuts are applied to patch of antenna, direction of
current changes which may cause antenna to resonate at different bands. When DGS is applied, direction of current flow
changes which causes variation in inductance and capacitance. It is to be noted that within particular area of ground
different DGS can produce different resonant frequencies and different bandwidth. In this paper two radiating rectangular
slot in ground plane have been cut out. Hence new resonances along with effective current paths are generate ding round
plane, as result wide band characteristics have been obtained. In order to formulate problem first of all literature survey
has been carried out. Work has been carried out and E-shaped fractal antenna was modified to make double E-shaped
antenna. As size of antenna [1] is small but it has not good characteristics, hence work has been carried out to make
antenna which has good characteristics.
2. BACKGROUND
OF ANTENNA
Nagpal et al. [1] proposed E-shaped fractal microstrip patch antenna with defected ground structure for wireless
applications. By applying different iterations of fractal geometry self-similar E shape structures are obtained. Khidre et al.
[2] presented U slot microstrip antenna for higher mode applications. This antenna was having bandwidth of 600 MHz
with a band from 5.17 GHz to 5.81 GHz. Gupta et al. [3] designed dual; band microstrip patch antenna for C Band and X
band applications. This antenna was having a patch with different slots so as to have good antenna characteristics. Janani
et.al [4] designed E-shaped fractal patch antenna for multiband applications. Fractal geometry had been used to obtain
multiband characteristics. Waladi et al. [5] designed fractal microstrip patch antenna using star triangular shape. Fractal
geometry had been applied on triangle to obtain star shape antenna. Ghorpade et al. [6] made a comparison between Eshape antenna and E-shaped fractal patch antenna. From this comparison it was found that fractal antenna gave
multiband characteristics. Kumar Raj et.al [7] proposed an ultra-wideband inscribed triangle circular fractal antenna.
Oraizi et al. [8] applied fractal geometry on square patch to improve antenna parameters. The proposed antenna had
circular polarization at one of its resonance frequencies, which was realized by producing a perturbation on its initial
structure and its broad banding might be achieved by placing an air gap. This antenna had dimensions of 30 mm.
Volume 3, Issue 6, June 2014
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International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 3, Issue 6, June 2014
ISSN 2319 - 4847
Substrate used was FR-4 with thickness of 1.6 and dielectric constant of 4.4. This antenna was used for GPS applications.
Behera et al. [9] had designed dual band fractal ring antenna by applying Minkowski fractal geometry. one side of ring of
square patch was replaced by fractal Minkowski curve. Chauhan et al. [10] designed crown fractal patch antenna with
small size of square of 20 mm. FR-4 had been used as substrate of thickness 1.6 mm and dielectric constant of 1.6 mm.
This antenna had been resonated at four different frequency bands which are 8.4 GHz, 10.6 GHz, 10.1 GHz and 11.3
GHz with small return loss.
3. ANTENNA DESIGN
E shape antenna in [11] is having large size of 150X 110 mm. This geometry was replaced by Wang E-shaped fractal
patch antenna so as to form fractal antenna [1] but this antenna had small size but not good characteristics to be used for
wireless applications, hence size of antenna is increased slightly. Minkowski fractal algorithm is used initially.
Fig 1: Fractal Geometry Used
One of most advantage of fractal geometry is size reduction and multiband characteristics. In order to make double Eshaped fractal microstrip patch antenna, first of all rectangle patch of dimensions 35X 29 mm2 is taken and coaxial feed is
given at feed point (3, 0, and 0). The FR-4 epoxy has been taken substrate of thickness 2 mm. The ground plane is having
dimensions of 49 X43 mm2 . Dimensions of antenna are mentioned in table 1.
Table 1: Dimensions of Double E-shaped Fractal Patch Antenna
Variable
Dimensions of patch
Dimensions of ground
Thickness of substrate
Substrate used
Feed point
Value
35 X 29 mm2
49 X 43 mm2
2 mm
FR-4
(3, 0, 0)
As the result of Zeroth iteration is obtained as shown in figure 2.
Figure 2: Zeroth Iteration
In order to obtain first iteration of fractal geometry, a slot of size 5X 25 mm2 has been cut out. Feed to antenna is given at
feed point (3, 9, and 0). Geometry of rectangular slot cut from patch is shown in figure 3.
Figure 3: Initiator Configuration
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International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 3, Issue 6, June 2014
ISSN 2319 - 4847
The iteration of fractal geometry is applied by making two cuts of square of size 5 mm on both sides to form slot antenna.
This antenna is having slot but it can be seen that two ‘E’ facing each other are formed. Feed to antenna is given at feed
point (5, 0, and 0). Geometry of this iteration is shown in figure 4.
Figure 4: First Iteration
Second iteration of fractal geometry is obtained by applying Minkowski fractal geometry algorithm on both sides. The
iteration is obtained by cutting slots of square of 1mm. In this way scale factor of one fifth is obtained. It is found that E
shape repeats itself. Feed to this antenna is given at (3, 0, 0) and antenna geometry is shown in figure 5.
Figure 5: Second Iteration
By applying fractal geometry on patch, multiband characteristics are obtained, further, effect of applying DGS is
analyzed. There are a number of DGS configurations, out of which plus shape DGS has been applied on ground plane of
antenna. This plus shape DGS configuration consist of two single rectangles having length 5 mm and width is 1 mm.
Antenna is fed by coaxial feed at (3, 0, and 0). DGS has been applied to geometry as shown in figure 6.
Figure 6: Antenna with DGS (a) Top View, (b) Rear View
It is found that area of also ground also decrease by applying DGS. One of disadvantage of applying DGS is that
efficiency of antenna decreases.
4. RESULTS AND DISCUSSION
Double E-shaped structure as shown in figure 6 is obtained by applying two iterations on fractal geometry on square patch
having rectangular slot. First four slots are cut so that double E shape structure is formed. Return loss versus frequency
for different iterations are shown in figure 7.
Volume 3, Issue 6, June 2014
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International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 3, Issue 6, June 2014
ISSN 2319 - 4847
Figure 7: Return Loss Vs. Frequency for Different Fractal Iterations of Double E-shaped FMPA
By applying second iteration of fractal geometry, antenna although resonates at single band When final iteration of fractal
geometry is applied structure as shown in figure 4.6 is obtained. This antenna had bandwidth of 615 MHz, 480 MHz,
640 MHz and 600 MHz with gain of 4.1 dBi, 4.5 dBi, 4.3 dBi and 4.15 dBi at corresponding frequencies.
Table 2 shows comparison of results of different iterations of fractal geometry applied on rectangular patch to form double
E-shaped fractal antenna as shown in figure 3. Results are analyzed in terms of antenna parameters.
Table 2: Comparison results of Different Iterations of double E-shaped FMPA
Iteration
Number
0th
Iteration
Initiator
by
cutting
slot
1st
2nd
Antenna
with
DGS
Resonance
Frequency
(GHz)
Return
Loss
(dB)
Gain
(dBi)
Band width
(MHz)
4
4.7
6.4
6.5
7.5
-16.24
-16.21
-20.85
-14.22
--23.17
2.38
0.5
-3.74
-1.16
1.77
120
150
165
150
250
8.4
-12.41
6.29
195
6.2
-18.51
2.77
300
5.1
7.8
8.7
9.6
5.1
7.8
8.7
9.6
-15.32
-14.23
--14.02
-18.54
-15.32
-14.19
--12.65
-17.54
4.07
4.41
4.40
3.75
4.1
4.5
4.3
4.15
550
400
650
520
615
480
640
600
From the table it is analyzed that as number of iterations are increased, results show improvement in terms of antenna
parameters. It has been found that multiband characteristics can be obtained by applying two iterations of fractal
geometry. When DGS can be applied to ground plane, bandwidth of antenna increases. There are different antenna
configurations out of which plus shape DGS have been used. This antenna as shown in figure 7resonates at 5.1 GHz, 7.8
GHz, 8.7 GHz and 9.6 GHz with return loss of -15.33 dB, -14.19 dB, 8.7 dB and -17.54 dB. This antenna had bandwidth
of 615 MHz, 480 MHz, 640 MHz and 600 MHz. Bandwidth of antenna increased as without DGS, antenna is having
bandwidth of 550 MHz, 400 MHz, 650 MHz and 520 MHz. This antenna configuration is having gain of 4.1 dBi, 4.5
dBi, 4.3 dBi and 4.15 dBi at corresponding frequency. Return loss versus frequency curve for DGS and without DGS has
been shown in figure 8.
Volume 3, Issue 6, June 2014
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International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 3, Issue 6, June 2014
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Figure 8: Return Loss Vs. Frequency for Antenna with DGS
By applying DGS, radiation pattern of antenna at frequency 5.1 GHz and 7.8 GHz has been shown in figure 9 is obtained.
(a)
(b)
Figure 9: Radiation Pattern of Antenna with DGS at (a) 5.1 GHz and (b) 7.8 GHz
Radiation pattern of antenna at frequency 8.7 GHz and 9.6 GHz has been shown in figure 10.
(a)
(b)
Figure10: Radiation Pattern of Antenna with DGS at (a)8.7 GHz and (b) 9.6 GHz
By applying DGS to antenna, results show improvement in bandwidth but slight increase in return loss. It is more
important to increase bandwidth. Comparison of antenna performance in terms of antenna characteristics is in table2.
Smith chart of double E-shaped fractal antenna has been shown in figure 11. It is best method of representing complex
impedance with respect to coefficients defined by the reflection coefficient. For analyzing impedance, admittance and for
solving transmission line problems, Smith chart is an important tool.
Figure 11: Smith Chart for proposed Antenna
Volume 3, Issue 6, June 2014
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International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 3, Issue 6, June 2014
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5. CONCLUSION
Initially rectangular patch is analyzed. It is not having good characteristics, so two iterations of fractal geometry are
applied to form double E-shaped fractal patch antenna. This resonates at four different bands with good bandwidth and
gain. Further to obtain wideband characteristics DGS(plus shape) has been applied hence antenna resonates at four bands
5.1 GHz, 7.8 GHz, 8.7 GHz and 9.6 GHz with good bandwidth. Parametric analysis has been performed in terms of
antenna characteristics by varying feed point and substrate thickness. This antenna found its application for WLAN
(wireless local area network), C band and X band applications.
References
[1] Nagpal A., Singh S. and Marwaha A., 2013. “Multiband E-Shaped Fractal Microstrip Patch Antenna with DGS for
Wireless Applications”, Proceedings of 5th IEEE International Conference on Computational Intelligence and
Communication Networks, Mathura, India,pp22-26.
[2] Khidre, Lee, Elsherbeni Z., and Fan Yang, 2013. “Wide Band Dual-Beam U-Slot Microstrip Antenna”, IEEE
TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 61, NO. 3, pp 1415-1418.
[3] Gupta, Singh S. and Marwaha A., 2013. “Dual Band U-Slotted Microstrip Patch Antenna for C band and X band
Radar”, Proceedings of 5th IEEE International Conference on Computational Intelligence and Communication
Networks, India, pp 41-45.
[4] Janani A., Priya A., 2013. “Design of E-Shape Fractal Simple Multiband Patch Antenna for S-Band LTE and
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[5] Waladi V., Mohammadi N., Zehforoosh Y., Habashi A. and Nourinia J., 2013. “A Novel Modified Star Triangular
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Propagation, Vol. 12, pp 651-654.
[6] Ghorpade, Babare and Deshmukh, 2013. “Comparison Of E-Shape Microstrip Antenna And E-Shape Fractal
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[7] Kumar Raj and Nikam B.2012. “A modified ground apollonian ultra wideband fractal antenna and its
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[8] Behera and Vinoy,2012. “Multi-Port Network Approach for the Analysis of Dual Band Fractal Microstrip Antennas”,
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[9] Oraizi Homayoon, Hedayati Shahram, 2012. “Miniaturization of Microstrip Antennas by the Novel Application of
the Giuseppe Peano Fractal Geometrices”, IEEE Transactions on Antennas and Propagation, Vol.60, No.8, pp 35593567.
[10] Chauhan S., Deegwal Jitendra K., Soni D. and Singodia P., 2012. “A Design of Crown Shape Fractal Patch
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[11] Bayatmaku.N, Lotfi P , Azarmanesh.M , and Soltani, 2011. “Design of Simple Multiband Patch Antenna For Mobile
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