In this paper, a stacked multi resonant slotted micro strip patch antenna (MPA) has been proposed which is suitable to be used for GSM, WLAN standard and WiMAX applications. The antenna has been designed using substrate of FR4 material. In the designed stacked antenna, substrates having different thickness has been used. The bottom stack of designed antenna has a radiating patch of circular shape and the patch on the upper stack has rectangular shape and is flexible in nature. The antenna has a feed line which is connected to circular patch to feed power to the antenna. The feed line has to be of suitable width to match the antenna impedance with port impedance of 50 ohms. The designed antenna has a defected ground structure in order to improve the antenna performance. The antenna performance has been measured in terms of antenna parameters such as impedance bandwidth (GHz), Return loss (dB), antenna impedance (ohms), VSWR and Directivity (dBi). The designed antenna results have been simulated in CST Microwave Studio 2010. The practically designed antenna has been tested successfully by using Network analyzer E5071C. It has been observed that the practical results closely match with theoretical results.

1. Int. Journal of Electrical & Electronics Engg. Vol. 2, Spl. Issue 1 (2015) e-ISSN: 1694-2310 | p-ISSN: 1694-2426
71 NITTTR, Chandigarh EDIT-2015
A Review of Multi Resonant Slotted Micro Strip
Patch Antenna (MPA) for IMT, WLAN &
WiMAX Applications
Tejinder Kaur Gill, Ekambir Sidhu, Amarveer Singh
Abstract: In this paper, a stacked multi resonant slotted micro
strip patch antenna (MPA) has been proposed which is
suitable to be used for GSM, WLAN standard and WiMAX
applications. The antenna has been designed using substrate
of FR4 material. In the designed stacked antenna, substrates
having different thickness has been used. The bottom stack
of designed antenna has a radiating patch of circular shape
and the patch on the upper stack has rectangular shape and is
flexible in nature. The antenna has a feed line which is
connected to circular patch to feed power to the antenna. The
feed line has to be of suitable width to match the antenna
impedance with port impedance of 50 ohms. The designed
antenna has a defected ground structure in order to improve
the antenna performance. The antenna performance has been
measured in terms of antenna parameters such as impedance
bandwidth (GHz), Return loss (dB), antenna impedance
(ohms), VSWR and Directivity (dBi). The designed antenna
results have been simulated in CST Microwave Studio 2010.
The practically designed antenna has been tested successfully
by using Network analyzer E5071C. It has been observed that
the practical results closely match with theoretical results.[11]
Index Terms— Micro strip patch antenna, Multi resonant air gap
stacked antenna, Defected ground structure, Return loss (S11),
Directivity, VSWR
I. INTRODUCTION1
Microstrip antenna, also known as printed circuit antenna
or patch antenna is suitable for conformal and low profile
applications. The Microstrip Patch Antenna has advantage
of low cost and weight, design flexibility and ease of
installation [4]. The radiating elements together with feed
line are photo etched on a thin dielectric sheet on a ground
plane. The patch can be square, rectangular or circular in
shape. However, MPA suffers from disadvantage that they
have narrow bandwidth. Extensive research has been
carried out to overcome the band width problem in recent
years and many techniques have been suggested and
implemented to achieve the desired wide band
characteristics [2][3]. One of these techniques is stacking
antennas, realizing dual frequency operation with two
resonant frequencies separated by certain range [8][9].
Stacked patch antenna is kind of microstrip which consists
of two printed antenna. The lower patch is called driven
patch and another patch is parasitically coupled to driven
patch. To produce broadband responses the selection of the
substrate of the first layer is very important. The current
distribution on the lower patch has an important role on the
bandwidth of the antenna. If the lower dielectric layer has a
greater dielectric constant than the upper layer, the
magnitude of the first order mode on the lower patch will
be greater than on the top patch thus the broadest
bandwidths can be achieved.
The thickness of each layer has an important role to obtain
broader bandwidth. In the design process the lower patch
does not design for minimum return loss in the desired
band, rather than the patch should be strongly capacitive
over this frequency range. To provide this, feed position of
the antenna become near the edge of the patch. The adding
of the second element moves the very capacitive
impedance region of the single patch locus to near a
matched condition [10]. The air gap can also be inserted
between the two stacked layers as air gap provides
maximum efficiency with minimum loss.
II. ANTENNA GEOMETERY
Fig 1 shows the top view of the bottom stack of the
antenna. The Fig1 shows circular slotted patch excited by
feedline of suitable width. Fig 2 represents the top view of
upper substrate. Fig 3 represents the bottom view of
stacked antenna. The ground has been
designed at the bottom of the lower stack which has been
partially reduced. The antenna has been fabricated using
FR4 as an substrate with dielectric constant of 4.4.The
height of lower substrate is 1.57mm and that of upper
substrate is 0.2mm.The feedline is designed in such a way
that antenna will have 50 ohm resistance matched with the
port impedance for maximum power transfer from port to
patch. The dimensions of substrate, patch, feed, slots cut on
patch and ground are listed in Table 2.

2. Int. Journal of Electrical & Electronics Engg. Vol. 2, Spl. Issue 1 (2015) e-ISSN: 1694-2310 | p-ISSN: 1694-2426
NITTTR, Chandigarh EDIT -2015 72
TABLE 2. ANTENNA PARAMETERS
Fig 1Top View of bottom stack of antenna
Fig 2 Top view of upper stack of antenna
Fig3 Bottom View of stacked antenna
NOTE:The dotted lines in Fig 3 represents the projection
of patch and feedline on ground.
3. SIMULATED RESULTS
The designed stacked antenna have been simulated
using CST Microwave Studio 2010 and the performance of
the antenna has been analyzed in terms of return loss,
VSWR, radiation pattern, directivity, impedance and gain.
The experimental results have been also obtained using
E5071C ENA series Network Analyzer and it has been
concluded that the practical results closely matches with
the simulated theoretical results. Fig 4 represents the
simulated results of return loss (S11) for designed stacked
antenna. It has been observed that the return loss is -34.70
dB at 1.8086 GHz, -25.418 dB at 2.944 GHz, -21.32 dB at
-3.2072 GHz, -20dB at 4.721 GHz and -30.774 dB at
5.310GHz. The simulated bandwidth of the proposed
antennas is 2.62841 GHz.
Antenna Parameter Specification
Length of substrate (Ls) 60mm
Width of substrate (Ws) 60 mm
Radius of lower patch (R1) 18.8mm
Radius of circular slot (R2) 10.8mm
Length of feed (Lp) 112mm
Width of feed (Wp) 5.6mm
Length (L1) 22mm
Length (L2) 21mm
Length (L3) 20mm
Width (W1) 13.2mm
Width (W2) 5.6mm
Width (W3) 4mm
Width (W4) 2mm
Width (W5) 2mm
Width (W6) 2mm
Length of upper substrate (LUs) 30mm
Width of upper substrate
(WUs)
30mm
Length of upper patch (LU1) 25mm
Width of upper patch (WU1) 11.6mm
Length of ground (Lg1) 12mm
Width of ground (Wg4) 60mm
Length of slot on ground (Lg5) 3mm
Width of slot on ground (Wg5) 6.4mm
Length (LU2) 30mm
Width (WU1) 24.2mm
Thickness of upper stack ( T1) 0.2mm
Thickness of lower stack ( T2) 1.57mm

3. Int. Journal of Electrical & Electronics Engg. Vol. 2, Spl. Issue 1 (2015) e-ISSN: 1694-2310 | p-ISSN: 1694-2426
73 NITTTR, Chandigarh EDIT-2015
Fig 4 Return loss of stacked MPA
Fig 5 shows that value of VSWR for stacked MPA is
less than 2 in the operating frequency range of 1.64 GHz
to 1.965 GHz, 2.75 GHz to 3.46 GHz, 4.35 GHz to 6.03
GHz.
Fig 5 VSWR plot of stacked MPA
4. EXPERIMENTAL VERIFICATION
The proposed antenna has been physically designed and
the top and bottom view of practically designed antenna
are shown in Fig 6(a) and Fig 6(b), respectively. The
designs are tested using E5071C ENA series Network
Analyzer. The practically analyzed results of slotted MPA
are shown in Fig 7. It has been observed from Fig 7 that
the practical results of designed MPA have return loss of -
38.25 dB at 1.85 GHz, -28.35 dB at 3.15 GHz and -20.420
dB and -27.385 at 4.97 GHz and 5.427 GHz respectively.
The bandwidth obtained from practical results of designed
MPA is 3.14 GHz.
Fig 6 (a) Top view of designed stacked MPA
Fig 6(b) Bottom view of designed stacked MPA
Fig 7 Experimental result of stacked MPA

4. Int. Journal of Electrical & Electronics Engg. Vol. 2, Spl. Issue 1 (2015) e-ISSN: 1694-2310 | p-ISSN: 1694-2426
NITTTR, Chandigarh EDIT -2015 74
5. CONCLUSION
From the above discussion, it can be concluded that the
stacked microstrip patch antenna has bandwidth of 3.14
GHz with operating frequency range between 1.43GHz
to 6.01 GHz .The VSWR for stacked microstrip patch
antenna is less than 2 in the operating frequency range
of 1.43 GHz to 6.01 GHz.
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[11] file:///C:/Users/good/Downloads/IJARCET-VOL-3-ISSUE-
10-3577-3585.pdf