Microstrip patch antennas are low profile , conformable, easy, inexpensive, and versatile in terms of realization and are thus been widely used in a various useful applications. This paper discusses different microstrip patch antennas designed over an operating frequency range 1.5 GHz using the substrate material Flame Retardant 4 (FR-4) lossy which has a dielectric constant of 4.3. These circuits were designed using Computer Simulation Technology (CST) Microwave Studio. The parameters such as return loss, efficiency and directivity are simulated, analyzed and compared.

1. IJSRD - International Journal for Scientific Research & Development| Vol. 2, Issue 07, 2014 | ISSN (online): 2321-0613
All rights reserved by www.ijsrd.com 659
Comparative Study and Designing of Different Radiating Patch in
Microstrip Patch Antenna
Shivani Chourasia1
Dr. Soni Changlani2
Miss. Pooja Gupta3
1
Research Scholar 2
Professor 3
Assistant Professor
1,2,3
Department of Electronics and Communication Engineering
1,2,3
Lakshmi Narain College of Technology & Science, Bhopal
Abstract— Microstrip patch antennas are low profile ,
conformable, easy, inexpensive, and versatile in terms of
realization and are thus been widely used in a various useful
applications. This paper discusses different microstrip patch
antennas designed over an operating frequency range 1.5
GHz using the substrate material Flame Retardant 4 (FR-4)
lossy which has a dielectric constant of 4.3. These circuits
were designed using Computer Simulation Technology
(CST) Microwave Studio. The parameters such as return
loss, efficiency and directivity are simulated, analyzed and
compared.
Keywords: Microstrip Patch Antenna, Microstrip line feed,
FR-4 (lossy) material, CST, Patch length, Return loss and
Efficiency
I. INTRODUCTION
A microstrip antenna consists of a very thin metallic patch
placed on conducting ground plane, separated by a dielectric
substrate [2]. A microstrip patch consists of a radiating patch
that may be square, circle, triangle, ring and rectangle etc. on
one side of a dielectric material substrate and a ground plane
on the other side. Microstrip antennas are preferred due to
their numerous advantages such as lightweight, low profile,
easy, inexpensive fabrication and simple modeling. They are
very versatile when chosen for a particular patch shape in
terms of polarization, pattern and resonant frequency [1].
They easily combine to form linear or planar arrays. There
are different feeding techniques in microstrip antenna like
microstrip line feed, coaxial probe feed, aperture coupling
feed, and proximity coupling feed [3-5].
The proposed work includes five microstrip patch
antenna designs that are designed for 1.5 GHz frequency
made by using microstrip line feed and simulated by
CST’10. A basic microstrip patch antenna is shown in Fig.1.
The operating frequency range of the proposed designs fall
under UHF frequency range. The antenna is designed for L-
band application.
Fig. 1: Basic Microstrip Patch Antenna
II. BASIC CHARACTERISTIC
Microstrip patch antennas, as shown in Fig.1, consist of a
very thin metallic strip (patch) placed over a substrate above
the ground plane. There are numerous substrates that can be
used for the design of microstrip antennas, and their
dielectric constant ‘ϵr’ are usually in the range of 2.2 ≤ ϵr ≤
12 [1]. The substrate dielectric constant used for microstrip
antenna is kept generally low (in the lower end of the range)
to reduce fringing field but for less critical applications [7].
Also, variation in dielectric constant is used for impedance
matching [8]. They provide better efficiency, larger
bandwidth, loosely bound fields for radiation into space. The
patch is generally made of conducting material such as
copper and gold.
A. Feed Selection
In this work, microstrip line feed is used as its main
advantage is that it is easy to fabricate, simple to match by
controlling the inset position and rather simple to model. It is
a patch added to the radiating patch using Boolean addition
option in CST software. On simulating the designs for
various feed lengths, it is observed that the feed can be
placed at any place within the patch length to match with its
input impedance (usually 50 ohm) as the difference in the
values of the parameters is negligible [9]. A microstrip line
feed is shown in Fig.2.
Fig. 2: Microstrip Line Feed
An equivalent circuit is shown below in Fig.3 .
Fig. 3: Equivalent Circuit for Microstrip Line Feed

2. Comparative Study and Designing of Different Radiating Patch in Microstrip Patch Antenna
(IJSRD/Vol. 2/Issue 07/2014/149)
All rights reserved by www.ijsrd.com 660
III. MODELING AND DESIGNING OF DIFFERENT MICROSTRIP
PATCH ANTENNA
The conducting patch can take any shape. It may be square,
rectangular, thin strip (dipole), circular, elliptical, triangular,
or any other configuration. The most popular are rectangular,
circular because of the ease of analysis and fabrication, and
their attractive radiation characteristics, especially low cross-
polarization radiation [1]. In this paper, we have taken five
radiating patches which are circle, rectangle, pentagon, I-
shaped and triangle [6-9], [11]. These designs were
simulated and analyzed on CST’10. The comparison was
made on the basis of maximum return loss (in dB) and
efficiency (in percent).
The substrate thickness was kept h = 1.6 mm while
the width and length of the ground plane and substrate is
50mm [10-11]. The substrate material used is FR-4 (lossy)
with dielectric constant ϵr = 4.3 which is less expensive for
fabrication [11-12]. These values were kept constant
throughout the work.
Every time when a patch was designed over the finite
substrate a slot was cut and a microstrip line feed was added
to the patch using tools available in CST’10. A feed was
given at the edge of the patch length. The designs were
simulated for frequency range 0 – 3 GHz.
A brief description is given for each of the five
patches designed.
A. Circular Patch
A circular patch antenna is designed on a finite grounded
dielectric substrate and feed length is varied to obtain the
desired frequency. Also, in this case, by varying radius of the
circular patch the resonant frequency can be varied.
In our work, for different radii, patch length is varied.
When patch length l of the antenna is adjusted at 25.5mm, we
obtained the maximum return loss = -41.606 dB at desired
operating frequency 1.503 GHz. Then efficiency is
calculated for the same frequency using farfield source. A
perspective view of circular microstrip patch antenna is
shown in Fig.4.
Fig. 4: 3D view of circular patch antenna in CST 2010
B. Pentagon Patch
A pentagon patch is designed using segments in a circle
design on a finite grounded dielectric substrate. Each time
for different radii of the circle, patch length l is varied and
the desired results are obtained at l = 40mm. We obtained the
maximum return loss -31.248 dB at desired frequency 1.509
GHz. A perspective view of pentagon microstrip patch
antenna is shown in Fig.5.
C. Rectangular Patch
The rectangular patch is by far most widely used
configuration among all radiating patch due to its ease in
designing. A slot is cut and microstrip line feed is added. The
length is varied and desired results are obtained at l =
37.4mm. A perspective view of rectangular microstrip patch
antenna is shown in Fig.6.
Fig. 5: 3D view of pentagon microstrip patch antenna in CST
2010
Fig. 6: 3D view of rectangular patch antenna in CST 2010
D. I-shaped Patch
This design is influenced with the idea of miniaturization and
is designed on a finite dielectric substrate placed over a
ground plane. It is easily formed by cutting two slots on both
sides of the reference axis from a rectangular patch. In this
case, the feed is given at the lower end of the I-shape. Width
of the slot and length of the patch is varied.
The desired results are obtained at patch length l =
21.11mm. A perspective view of I-shaped microstrip patch
antenna is shown in Fig.7.

3. Comparative Study and Designing of Different Radiating Patch in Microstrip Patch Antenna
(IJSRD/Vol. 2/Issue 07/2014/149)
All rights reserved by www.ijsrd.com 661
Fig. 7: 3D view of I-shaped patch antenna in CST 2010
E. Triangular Patch
The triangular patch antenna is also designed using segments
in the circle design placed over substrate. The same
procedure as in case of pentagon microstip patch antenna is
followed and patch length l is varied. The maximum return
loss = -46.259dB is obtained for 1.506 GHz with l = 30mm.
A perspective view of triangular microstrip patch antenna is
shown in Fig.8.
Fig. 7: 3D view of I-shaped patch antenna in CST 2010
A. Triangular Patch
The triangular patch antenna is also designed using segments
in the circle design placed over substrate. The same
procedure as in case of pentagon microstip patch antenna is
followed and patch length l is varied. The maximum return
loss = -46.259dB is obtained for 1.506 GHz with l = 30mm.
A perspective view of triangular microstrip patch antenna is
shown in Fig.8.
Fig. 8: 3D view of triangular patch antenna in CST 2010
IV. RESULT
All five radiating patches are simulated and analyzed. It is
found that the triangular patch antenna had the maximum
return loss = -46.259dB with appreciable efficiency 61.74%.
Fig.8 shows 3D view of triangular microstrip patch antenna.
Also, its return loss graph in Fig.10 depicts the same with the
radiation pattern displayed in Fig.11.
The highest efficiency resulted for rectangular
microstrip patch antenna = 71.34% with return loss = -
26.854 dB that was 20 dB less than that of triangular one.
Also, it was seen that the I-shaped patch antenna was with
minimum return loss = -20.595 dB and lowest efficiency =
41.04%.
The comparison between the five radiating patches in
terms of their various parameters is shown in Table I. The
data is plot in the graph which is shown in Fig.12.
Fig. 9: Polar plot for s-parameter of triangular patch antenna
S.N
o.
Parame
ters
Circl
e
Penta
gon
Rectan
gle
I-
shap
e
Trian
gle
1
Return
Loss
(in dB)
-
41.6
06
-
31.248
-
26.854
-
20.5
95
-
46.25
9
2
Efficien
cy
(in dB)
-
3.46
5
-3.736 -3.376
-
8.90
6
-4.821
3
Efficien
cy
(in
percenta
ge)
70.7
1%
68.82
%
71.34
%
41.0
4%
61.74
%
4
Frequen
cy
(in GHz)
1.50
3
1.509 1.506 1.5 1.506
5
Patch
Length
(in mm)
25.5 40 37.4
21.1
1
30
Table 1: Comparison between Different Micro strip Patch
Antenna Designs

4. Comparative Study and Designing of Different Radiating Patch in Microstrip Patch Antenna
(IJSRD/Vol. 2/Issue 07/2014/149)
All rights reserved by www.ijsrd.com 662
Fig. 10: Simulated graph of triangular patch antenna in CST
2010
Fig. 11: Radiation pattern of Triangular Patch Antenna
Fig. 12: Comparison between Return loss of different
microstrip patch antenna
V. CONCLUSION
From the above results, we can say that for miniaturization at
1.5 GHz that has wide applications in military telemetry,
GPS, mobile phones GSM (Global System for Mobile
Communication) and amateur radio, triangular microstrip
patch antenna provides the best results with good trade-off
between return loss and efficiency. The simulated antenna
using FR-4 (lossy) material as substrate and microstrip line
feeding technique in CST 2010 software is shown in Fig.8.
VI. FUTURE DEVELOPMENT
Though new designs for radiating patch is shown in this
project , it can further be explored by introducing more new
shapes of patch antennas such as linear or array pattern for
the future research. This may also include different type of
substrates with diverse permittivity. Although the return loss
of the patches are increased, there are still rooms for
improvement such as the overall size of the antenna
including the substrate is not much reduced by using this
method, future investigation and research need to be done in
order to reduce overall size of the antenna while maintaining
another antenna performances.
ACKNOWLEDGMENT
I am highly grateful to Miss. Pooja Gupta, Assistant
Professor at LNCTS for giving me invaluable guidance in the
field of antenna and providing me the opportunity to carry
out this work further. I also present my gratitude to Dr. Soni
Changlani, Professor at LNCTS. It was their essential
encouragement that enabled me to pursue my work in this
field.
REFERENCES
[1] Antenna Theory, C. Balanis, Wiley, 2nd
edition,
Chapter 14, ISBN 0-471-59268-4, 1997.
[2] Mamta Devi Sharma, Abhishek Katariya, Dr. R. S.
Meena, “E-shaped patch microstrip antenna for wlan
application using probe feed and aperture feed”,
International Conference on Communication Systems
and Network Technologies, 2012.
[3] I.J. Bahl and P. Bhartia, Microstrip Antennas, Artech
House, Dedham, MA, 1980.
[4] J. R. James and P. S. Hall, Handbook of Microstrip
Antennas, Peter Peregrinus, London, UK, Vols. 1 and
2, 1989.
[5] R. E. Munson, “Microstrip Antennas,” Chapter 7 in
Antenna Engineering Handbook (R. C. Johnson and
H. Jasik, eds.), McGraw-Hill Book Co., New York,
1984.
[6] A. Vishwapriya, S. Banu, R. Yogamatthi, “Design and
analysis of I-shaped MIMO antenna for wireless
applications”, Computing, Communications and
Networking Technologies (ICCCNT), 4th
International Conference, 2013.
[7] D. M. Pozar, “Microstrip Antennas,” Proc. IEEE, Vol.
80, No. 1, pp. 79–81, January 1992.
[8] Prasanna L. Zade, Sachin S. Khade, Dr. N. K.
Choudhary, “Modeling and designing of circular
microstrip antenna for wireless communication”
Second International Conference on Emerging Trends
in Engineering and Technology, 2009.
[9] M.M. Sharma, N. C. Bajia, Vinita Agarwal, Shilpi
Kumawat, Swati Gupta and R.P. Yadav, “Compact
microstrip circular patch antenna for Wi-Max with
double-layered substrate”, International Conference
on Microwave – 08, 2008.

5. Comparative Study and Designing of Different Radiating Patch in Microstrip Patch Antenna
(IJSRD/Vol. 2/Issue 07/2014/149)
All rights reserved by www.ijsrd.com 663
[10]Subodh Kumar Tripathi, Vinay Kumar, “E-shaped
slotted microstrip antenna with enhanced gain for
wireless communication”, International Journal of
Engineering Trends and Technology - July to Aug
Issue 2011.
[11]P. K. Singhal, B. Garg, and N. Agrawal, “A high gain
rectangular microstrip patch antenna using ‘different c
patterns’ metamaterial design in L-band,” Advanced
Computational Techniques in Electromagnetics, vol.
2012, pp. 1–5, 2012.
[12]Sohag Kumar Saha, Amirul Islam Rony, Ummay
Habiba Suma, Md. Masudur Rahman, “E-Shape
microstrip patch antenna design for wireless
applications”, International Journal of Science,
Engineering and Technology Research (IJSETR),
Volume 2, Issue 3, March 2013.