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International Journal of Scientific and Research Publications, Volume 2, Issue 2, February 2012 1 ISSN 2250-3153
www.ijsrp.org
Comparative Analysis of Microstrip Coaxial Fed, Inset
Fed and Edge Fed Antenna Operating at Fixed
Frequency
B. Jyothi, B.T.P.Madhav, V.V.S. Murthy, P. Syam Sundar, VGKM Pisipati
Department of ECE, K L University, Guntur DT, AP, India
Abstract- There are so many techniques are available for
feeding the microstrip patch antennas and each are having their
own significance and impact on these antennas. The functional
characteristics and output parameters of these microstrip
antennas will be affected by choosing different feeding
techniques. This paper deals with the comparative analysis of
coaxial, inset and edge fed MSPA’s with their simulated
performance characteristics. All the three models are designed
and simulated using Finite Element Method based antenna
designing software Ansoft HFSS.
Index Terms- coaxial feeding, inset feeding, edge feeding,
FEM.
I. INTRODUCTION
icrostrip patch Antennas has various advantages such as
low profile, light weight, easy fabrication. Feed line is
used for excite to radiate by direct or indirect contact. Microstrip
patch antennas can be fed in a variety of ways.1.Contacting
2.Non-Contacting.
In contacting method the RF power is fed directly to the
radiating patch using a connected element, they are microstrip
feed and coaxial feed [1].
In Non Contacting method, electromagnetic coupling is done
to transfer the power between the feed line and the radiating
patch, they are Aperture coupled feed and Proximity coupled
feed [2].
II. FEEDING TECHNIQUES
Microstrip line feed is one of the easier methods to fabricate as
it is a just conducting strip connecting to the patch and therefore
can be consider as extension of patch. It is simple to model and
easy to match by controlling the inset position. The disadvantage
of this method is that as substrate thickness increases, surface
wave and spurious feed radiation increases which limit the
bandwidth [3-4].
In Coaxial feeding, the inner conductor of the coaxial is
attached to the radiation patch of the antenna while the outer
conductor is connected to the ground plane. The main advantages
of this method are easy to fabricate, easy to match and low
spurious radiation [5-6].
Aperture coupling consist of two different substrate separated
by a ground plane. On the bottom side of lower substrate there is
a microstrip feed line whose energy is coupled to the patch
through a slot on the ground plane separating two substrates. Top
substrate uses a thick low dielectric constant substrate, and the
bottom substrate uses high dielectric substrate. The ground plane,
which is in the middle, isolates the feed from radiation element
and minimizes interference of spurious radiation for pattern
formation and polarization. The main advantage of this method is
allows independent of feed mechanism element [7-8].
Proximity coupling has the largest bandwidth, has low
spurious radiation. Length of feeding stub and width-to-length
ratio of patch is used to match
Fig. 1 Coaxial Fed Rectangular Patch Antenna
Fig. 2 Inset Fed Rectangular Patch Antenna
M
International Journal of Scientific and Research Publications, Volume 2, Issue 2, February 2012 2
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Fig. 3 Edge Fed Rectangular Patch Antenna
Figure (1) shows the coaxial fed Microstrip rectangular patch
antenna designed to work at 5.2 GHz. Figure (2) shows the Inset
fed microstrip rectangular patch antenna designed to work at 5.2
GHz. Figure (3) shows the Edge fed microstrip rectangular patch
antenna designed to work at 5.2 GHz.
III. RESULTS AND ANALYSIS
Fig. 4 Return Loss Vs Frequency
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Fig. 5 2D Gain
Return loss is the difference, in dB, between the forward and
reflected power measured at a given point in an RF system. A
mismatched antenna reflects some of the incident power back
toward the transmitter and since this reflected wave is traveling
in the opposite direction as the incident wave, there will be some
points along the cable where the two waves are in phase and
other points where the waves are out of phase. The return loss
obtained for three models is shown in figure (4). The return loss
obtained for three models are -26.52, -12.02, -10.87 dB
respectively. The return loss is increasing when we select edge
feeding and inset feeding compared with coaxial feeding.
Fig. 6 Contour Plot for radiation pattern in Phi direction
The gain of the antenna in given direction is the amount of
energy radiated in that direction compared to the energy an
isotropic antenna would radiate in the same direction when
driven with the same input power. The direction in which the
antenna is radiating its most of its power is called its gain. The
gain obtained for three models are 7.93, 7.95 and 7.45 dB
respectively. The gain is marginally high for the inset feed
antenna and slightly less for edge feed antenna.
The radiation pattern of the antenna can be defined as the spatial
distribution of a quantity that characterizes the electromagnetic
field generated by an antenna. Figure (6) and (7) shows the
radiation pattern contour plots of the antenna in phi and theta
directions. The contour plots represent the radiation pattern in
elevation and azimuthal angles. The radiation pattern represents
the energy radiated from the antenna in each direction, often
pictorially.
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Mesh generation is the practice of generating a polygonal or
polyhedral mesh that approximates a geometric domain to the
highest possible degree of accuracy. The term "grid generation"
is often used interchangeably. Typical uses are for rendering to a
computer screen or for physical simulation such as finite element
analysis or computational fluid dynamics. Figure (8) shows the
current distribution on the patch of the antenna for three models
of feeding.
Fig. 7 Contour Plot for radiation pattern in Theta direction
Fig. 8 Current Distribution over the patch in three types of feeding
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Table (1) and (2) shows the antenna additional parameters and the maximum field data.
Antenna Parameters
Table 1: Antenna Parameters
Quantity Probe-fed(Value/Units) Edge-fed(Value/Units) Inset-fed(Value/Units)
Max U 0.0031973W/Sr 0.0032096W/Sr 0.004259W/Sr
Peak Directivity 6.3038 5.7038 6.3612
Peak Gain 6.2126 5.5625 6.2422
Peak Realized Gain 4.0711 4.0334 5.3522
Radiated Power 0.0063739W 0.0070715W 0.0084138W
Accepted Power 0.0064675W 0.0072511W 0.0085742W
Incident Power 0.0098694W 0.01W 0.01W
Radiation Efficiency 0.98553 0.97522 0.98129
Front to Back Ratio 144.83 83.426 386.19
Maximum Field Data
Table 2: Maximum Field Data
rE field Probe -fed
(value/units)
Probe-
fed
(at phi)
Probe-
fed (at
theta)
Edge-fed
(value/units)
Edge-
fed (at
phi)
Edge-
fed
(at
theta)
Insert-fed
(value/units)
Insert-
fed
(at phi)
Insert-fed
(at theta)
TOTAL 1.5527v 90deg -4deg 1.5557v 90deg 6deg 1.729v 90deg 6deg
X 0.34194v 135deg 52deg 0.29898v 130deg 60deg 0.31079v 45deg 56deg
Y 1.5506v 85deg -2deg 1.5518v 95deg 2deg 1.7863v 85deg 4deg
Z 0.74523v 90deg -44deg 0.82391v 90deg 46deg 0.85778v 90deg 44deg
PHI 1.5473v 180deg 0deg 1.5472v 180deg 0deg 1.7761v 180deg 0deg
THETA 1.5527v 90deg -4deg 1.5556v 90deg 6deg 1.792v 90deg 6deg
LHCP 1.1365v 10deg -10deg 1.1116v 125deg 16deg 1.2736v 125deg 8deg
RHCP 1.131v 170deg -10deg 1.112v 55deg 16deg 1.277v 55deg 8deg
IV. CONCLUSION
Different types of feeding techniques are applied to
rectangular patch antenna and its performance characteristics
are observed at fixed frequency. Coaxial feeding is giving
better return loss and inset feeding is giving superior gain
compared to the other feeding techniques. Radiation efficiency
is showing better result for coaxial feeding and radiated power
is high for the case of edge feeding. The inset and edge
feeding are easier in construction. Overall the coaxial feeding
is giving better input impedance and other parameters
compared to other different feeding techniques. The only
problem is with the coaxial feeding is its design complexity.
ACKNOWLEDGEMENT
The authors like to express their thanks to the department
of ECE and management of K L University for their
continuous support and encouragement during this work.
Further, VGKM Pisipati acknowledges the financial support
of Department of Science and Technology through the grant
No.SR/S2/CMP-0071/2008.
REFERENCES
[1] P.J.Soh, M.K.A.Rahim, A.Asrokin & M.Z.A.Abdul Aziz, Design, Modeling, and performance comparison of feeding techniques for a
microstrip patch antenna. Journal Teknologi, 47 (D) Dis.2007: 103-120
universiti technologi Malaysia. [2] Kazuhiro Kitatani, Sadahiko Yamamoto. Coaxial feed-type microstrip
patch antenna with variable antenna height. Electronics and
Communications in Japan (Part I: Communications), Volume 87, Issue 2, pages 10–16, February 2004.
[3] B.T.P.Madhav, K.Praveen Kumar, N.Srinivas Sri Chaitanya, P.Rakesh
Kumar, N.V.K.Ramesh, B.Nagaraju Nayak, Comparative Analysis of Shorting Pin and Shorting Plate Models for Size Reduction in the
Microstrip Patch Antennas, International Journal of Communication Engineering Applications-IJCEA,ISSN: 2230-8504; e-ISSN-2230-
8512Vol 02, Issue 04; July 2011
[4] K. F. Lee, K. M. Luk, K. F. Tong, S. M. Shum, T. Huynh, and R. Q. Lee, “Experimental and simulation studies of the coaxially fed U-slot
rectangular patch antenna,” Inst. Elect. Eng. Microwave Antennas
Propagation, vol. 144, no. 5, pp. 354–358, Oct. 1997. [5] Y. X. Guo, C. L. Mak, K. M. Luk, and K. F. Lee, “Analysis and design
of L-probe proximity fed-patch antennas,” IEEE Trans. Antennas
Propagat., vol. 49, pp. 145–149, Feb. 2001. [6] K. M. Luk, C. L. Mak, Y. L. Chow, and K. F. Lee, “Broadband
microstrip patch antenna,” Electron. Lett., vol. 34, no. 15, pp. 1442–
1443, 1998.
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[7] Zhang, Y.P. and J.J. Wang, 2006. Theory and analysis of differentially-
driven microstrip antennas. IEEE Transactions on Antennas and Propagation, 54(4): 1092-1099.
[8] Mak, C.L. and K.M. Luk, 2000. Experimental study of a microstrip
patch antenna with an L-shaped probe. IEEE Transactions on Antennas and Propagation, 48(5): 77-78.
AUTHORS
First Author – B.T.P.Madhav was born in India, A.P, in 1981. He
received the B.Sc, M.Sc, MBA, M.Tech degrees from Nagarjuna
University, A.P, India in 2001, 2003, 2007, and 2009 respectively.
From 2003-2007 he worked as lecturer and from 2007 to till date he
is working as Assistant Professor in Electronics Engineering. He has
published more than 70 papers in International and National journals.
His research interests include antennas, liquid crystals applications
and wireless communications.
Second Author – B.Jyothi, was born in A.P, India in 1981. She
completed her B.Tech in 2003 from CR Reddy College of
Engineering affiliated to Andhra University. Presently she is pursuing
her M.Tech, in Communications and Radar Systems from K L
University.
Third Author – Prof. VGKM Pisipati was born in India, A.P, in
1944. He received his B.Sc, M.Sc and Ph.D degrees from Andhra
University. Since 1975 he has been with physics department at
Acharya Nagarjuna University as Professor, Head, R&D Director. He
guided 22 PhDs and more than 20 M.Phils. His area of research
includes liquid crystals, nanotechnology and liquid crystals
applications. He visited so many countries and he is having more than
260 International research publications. He served different positions
as academician and successfully completed different projects
sponsored by different government and non-government bodies. He
is having 5 patents to his credit.
Fourth Author – V.V.S.Murthy was born on 02 January, 1981. He
received his B.E. and M.Tech degrees in 2002 and 2006 respectively.
He is a life member of IETE and ISTE. His research areas include
Antennas and Radio wave propagation and optical image processing.
Currently he is working as Associate Professor in ECE department of
K.L.University, Guntur.