Design of rectangular microstrip patch antenna

Abstract

The purpose of this paper is to design a microstrip rectangular antenna in Advance Design System Momentum (ADS). The resonant frequency of antenna is 4.1GHz. The reflection coefficient is less than −10dB for a frequency range of 3.1GHz to 5.1 GHz. The proposed rectangular patch antenna has been devise using Glass Epoxy substrate (FR4) with dielectric constant (er = 4.4), loss tangent (tan δ) equal to 0.02. This rectangular patch is excited using transmission lines of particular length and width. Various parameters, for example the gain, S parameters, directivity and efficiency of the designed rectangular antenna are obtained from ADS Momentum.

Full text

Design of Rectangular Microstrip Patch Antenna
Houda Werfelli, Khaoula Tayari, Mondher Chaoui, Mongi Lahiani, Hamadi Ghariani
National Engineers school of Sfax
Laboratory of Electronics and Technology of Information (LETI)
Sfax, Tunisia
werfelli.houda@yahoo.fr
Abstract
—
The purpose of this paper is to design a
microstrip rectangular antenna in Advance Design
System Momentum (ADS). The resonant frequency of
antenna is 4.1GHz. The reflection coefficient is less than -
10dB for a frequency range of 3.1GHz to 5.1 GHz. The
proposed rectangular patch antenna has been devise
using Glass Epoxy substrate (FR4) with dielectric
constant (єr = 4.4), loss tangent (tan δ)
equal to 0.02. This
rectangular patch is excited using transmission lines of
particular length and width. Various parameters, for
example the gain, S parameters, directivity and efficiency
of the designed rectangular antenna are obtained from
ADS Momentum.
Keywords— Ultra Wide Band; Microstrip; rectangular
patch antenna; bandwidth; Return Loss ; ADS Momentum.
I. I
NTRODUCTION
The Federal Communication Commission (FCC)
specified some rules for Ultra Wideband (UWB)
system communication; it has authorized the use of
UWB communication in the frequency band of 3.1 to
5.1 GHz at a spectral density equal to -41.3dBm/ MHz.
Radar systems have been used for various applications
such as monitoring and remote sensing. Radar remote
sensing techniques have become interesting to
researchers. Ultra Wideband radar system based on the
transmission of short duration pulses. The principle of
this radar is transmitting a short duration pulses and
then detecting the reflected pulse response [1].
In the UWB radar system, an antenna plays a very
important place. This is one among the important
features of the transceiver chain. An antenna both
transmitting and receiving the pulse wave. The last
element is designed to radiates and receiving a signal
carrying an information to be processed.
The microstrip UWB antennas is one of the most
commonly used antennas in radar applications. It has
attracted a lot of attention because of their advantages
such as ease of fabrication simple structure, easy
integration with microwave integrated circuits.
Geometric shape of a microstrip antenna comprises a
radiating element on the dielectric substrate and on the
other side a ground plane, as illustrated in Fig 1. There
are several category of the microstrip patch antenna, can
be cited some example the circular, a square radiating
element, triangular, semicircular..., but the most
common is rectangular element [2][3].
The study and the design of rectangular patch antenna is
presented in this research paper. We begin first with
schematic model of the rectangular patch antenna.
After, the different simulations of circuit conceived are
studied and we finish by conclude our work.
Fig.1. Rectangular Patch Antenna
II. F
EEDING
T
ECHNIQUES
O
F
M
ICROSTRIP
A
NTENNA
The patch antennas may be powered with many
methods. The processes feeding are categorized in two
methods:
• In category contacting, the feeding technique is
powered by means of a connecting element such
as a microstrip line into the radiating patch.
• Without contact category, a transfer of power
between the microstrip line and radiating
element is performed with the electromagnetic
field coupling.
The most famous feeding techniques employed in the
microstrip patch antenna are: coaxial probe, feeding
technique with microstrip line and aperture or proximity
coupling methods.
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A. Feeding Techniques
In this kind of feeding process (Fig.2), the edge of
the microstrip patch is connected directly to a
conducting strip. This feeding method offers the benefit
that the conducting line can have the opportunity of
engraved on same substrate of patch antenna providing
a planar shape. The width of conducting element is
smaller as compared at the patch antenna.
Fig .2.Microstrip line technique
B. Coaxial Probe Feeding Techniques
The outside conductor of a coaxial connector
attached at ground plane, while the inside is extends
across the dielectric and is welded at the radiating
element antenna.
However, the disadvantage of this technique is a
difficult to model and produce à narrow bandwidth.
Figure 3 show this type of feed technique.
Fig.3. Coaxial Probe Feed
C. Feeding Techniques With Proximity coupled
This feeding technique (Fig.4) utilized two dielectric
substrates in order that the feed line, firstly, is between
two substrates and on the other hand the radiating
element is on top of the upper substrate.
Fig.4.Proximity coupled Feed
D. Aperture coupled feed
This type of feed technique (Fig.5), a microstrip
feed line is separated by the ground plane to the
radiating patch.
The feed line and the radiating element is coupled
through an aperture or a slot in the ground plane . The
variations in the coupling will depend of width and
length of the slot to improve the simulation result of
bandwidths and return losses. The slot is usually
centered under the radiating element [4] [5].
Fig.5.Aperture coupled feed
III. D
ESIGN
R
ECTANGULAR
P
ATCH
A
NTENNA
A rectangular microstrip antenna is conceived for
a UWB system communication application, which is
operating at a frequency of 4.1 GHz. The proposed
rectangular patch antenna has been conceived utilizing
the substrate Fr4 with dielectric equal to εr = 4.4 and
height of substrate (h) = 1.6 mm. This microstrip
antenna is working at a frequency of 3 GHz to 5 GHz
[6] [7].
The basic steps for the development of rectangular
patch antenna (RPA) are:

Step 1: A parameter Width of the radiating RPA is
compute from this equation:
1
2
2+
=
rr
f
C
W
ε
(1)
Where:
c: velocity of light, 3*108m/s,
εr :dielectric constant of the substrate.
fr : resonant frequency of antenna
Step 2: Effective Dielectric constant of the PRA is
determined as:












+
−
+
+
=
W
h
rr
eff
2
1
1
2
1
2
1
εε
ε
(2)
Step 3: The effective length is specified at the
resonance frequency
eff
eff
fr
C
L
ε
2
=
(3)
Step 4: Extension length of the PRA
compute with this
equation:
()
()





+−





++
=Δ
8.0258.0
264.03.0
*412.0*
h
W
h
W
hL
eff
eff
ε
ε
(4)
The length " L" of the PRA is calculates as:
LLL
eff
Δ−= 2
(5)
The patch dimension is W=22.26 mm * L=16.95 mm.
The feed dimension is WL= 3.1 mm *LL=10.4 mm.
The ground plane length and width are calculated as
Lg=26.55 mm
and Wg= 31.86 mm
respectively.
The proposed rectangular patch antenna is designed
using electromagnetism simulation software ADS.
The Equivalent circuit of the rectangular patch antenna
of 4.1 GHz in ADS schematic is presented in Fig. 6
where :
The component Mloc: refers the dimensions (W, L) of
the patch antenna.
The component Mlin: designates a feed line
The component M step: adapting the patch and the feed
line, expanding the band by varying its dimensions.
Fig.6. Schematic model of the rectangular antenna (PRA)
Return loss simulation result of the schematic model of
rectangular antenna is shown in Fig.7.
Fig .7.Return loss (S11)
After the simulation of the rectangular patch antenna, it
was found that the band is very narrow comparing to
the standard bandwidth (UWB) which is 2 GHz, which
is insufficient for the good running of our antenna. And
to optimize, we use the function GOAL (ADS
schematic) [8].
For optimization our antenna circuit, the intention is
to fit the value of reflection coefficient (S11 ) at the
bandwidth, the goal function is to make a value S11 at
-10 dB for a bandwidth between 3-5GHz. A Goal
234516
-15
-10
-5
-20
0
freq, GHz
dB(S(1,1))
m1
m1
freq=
dB(S(1,1))= -19.54
5
4.160GHz

function are put from the ADS tools palette into the
circuit designed , as presented in Fig. 8 .
Fig.8. Optimized schematic model of the rectangular antenna
Figure 9 shows the return loss amplitudes depending of
the frequency of conceived UWB antennas. The
obtained results indicate that the antenna has UWB
characteristics in the whole frequency band with a
return loss below -10 dB, the bandwidth (band
frequency is 3 at 5 GHz) is obtained and the
resonance frequency is 4.3GHz.
Fig.9. Return loss of optimized PRA
Figure 10 shows the simulated result of VSWR against
frequency (GHz). Voltage standing wave ratio
(VSWR) parameter varies usually from 1.5 to 2 in the
frequency range 3 GHz to 5 GHz [8]. Starting at
simulated result, the rectangular patch antenna present
the best characteristic of VSWR in the band frequency.
It complies with the VSWR equal to 1.8.
Fig.10. VSWR simulation result
IV. L
AYOUT
M
ODEL OF
T
HE RECTANGULAR
P
ATCH
A
NTENNA
The layout window is used for the physical design
of the model. The physical design can be created
directly in the layout window, or be designed in the
schematic and then converted into the layout window.
Fig.11.Layout shape of the rectangular antenna
Figure 12 show the return loss (S1, 1) simulation result
of the optimized rectangular patch in ADS Momentum.
It is clear from the figure that the patch resonates at 4.3
GHz and has minimum loss at the resonant frequency
of -14 dB.
The radiation pattern of UWB rectangular microstrip
antenna is depicted below (Fig .13). We are getting one
lobe (main lobe) which corresponds to the theoretical
radiation pattern of patch antenna radiant.
2468010
-15
-10
-5
-20
0
fre
q,
GHz
dB(S(1,1))
23456789110
2
3
4
1
5
freq, GHz
VSWR1

Fig.12.Return loss antenna simulation
(a)
(b)
Fig.13.3D radiation pattern: (a) Front view, (b) Opposite view
Table I shows the simulation of directivity and gain of
microstrip antenna with rectangular patch. Directivity,
Gain and power radiated are important parameters to
determine the efficiently of antenna. Gain of 3.48 is
achieved.
TABLE I. Antenna Parameters
Power radiated
(Watts)
0.4949
Effective angle ( degrees) 159.60
Directivity (dB) 6.5430
Gain (dB) 3.488
Maximum intensity
(Watts/ Steradian)
0.17762
V. H
FSS
S
IMULATION
The results of simulation of rectangular patch
antenna made by software Ansoft High Frequency
Structure Simulator (HFSS) is shown on Fig. 14.
Fig.14.HFSS model of microstrip antenna with rectangular patch
The simulation of the rectangular patch antenna by
means of HFSS, it was found that the band is
acceptable comparing to the standard bandwidth which
ranges 3 to 5 GHz; the resonance frequency is 4.3 GHz
and the return loss S11 equal to -30 dB.
2345617
-10
-5
-15
0
Frequency
M
ag.
[dB]
S11

Fig.15. Return loss of HFSS simulation antenna
Figure 16 describes the simulated result of VSWR .A
VSWR value varies from 1.6 to 1.7 throughout the
frequency range from 3GHz to 5GHz.
Fig.16.Voltage standing wave ratio
This difference in resonant frequency is returns from to
the typical of software simulation because ADS is most
focused on planar stuff but HFSS is much more
sophisticated tool 3D
.
VI. C
ONCLUSION
The conception and simulation of rectangular
microstrip patch antenna that operates in UWB
frequencies was successfully designed using advanced
design system. From observing the return loss, VSWR,
it is very clear that this antenna works on the designed
UWB frequency range. This research, detailed the
designing of our UWB rectangular antenna in the
Advanced Design System and Ansoft High frequency
structure simulator.
As the outlook work, we may extend our research to
study a various slot antenna in affects the resonance
frequency and the bandwidth.
R
EFERENCES
[1] Yong-Xin Guo; Kah- Wee Khoo; Ling Chuen Ong "Wide band
Circularly Polarized Patch Antenna Using Broadband Baluns"
Antennas and Propagation, IEEE Transactions on Volume 56, Issue
2, Feb. 2008.
[2] A.H.M. Zahirul Alam, Md. Rafiqul Islam and Sheroz Khan "
Design and Analysis of UWB Rectangular Patch Antenna ", Pacific
conference on applied electromagnetiggs proceedings, December 4-
6 , 2007, Malaysia.
[3]
Werfelli Houda, Mondher Chaoui, Hamadi Ghariani, and
Mongi Lahiani. "Design of a pulse generator for UWB
communications", 10th International Multi-Conferences on Systems
Signals & Devices 2013 (SSD13), 2013.
[4] Mahdi Ali, Abdennacer Kachouri and Mounir Samet "Novel
method for planar microstrip antenna matching impedance", Journal
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[5] S. Siva sundara pandian, Dr. C.D. Suriyakala" Novel Octagonal
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Communication Engineering (IOSR-JECE), Sep-Oct. 2012.
[6] Mustafa K. Taher Al-Nuaimi and William G. Whittow " On The
Miniaturization of Microstrip Line-Fed Slot Antenna Using Various
Slots" Final author version. IEEE Loughborough Antennas and
Propagation Conference (LAPC), Loughborough, UK, 2011.
[7] Aruna Rani, R.K. Dawre "Design and Analysis of Rectangular
and U Slotted Patch for Satellite Communication" International
Journal of Computer Applications , December 2010.
[8] Dhivya N, Pooja Jayakumar, Prashanth Mohan, Rekha Zacharia,
Vishnupriya Vasudevan, G. Prabha" Comparative Study Of Slotted
Microstrip Antenna Fed Via A Microstrip Feed Line" Proceedings of
1st IRF International Conference, Coimbatore, 9th March-2014.
1.00 2.00 3.00 4.00 5.00 6.00 7.00
Freq [GHz]
-35.00
-30.00
-25.00
-20.00
-15.00
-10.00
-5.00
0.00
dB (S (1 ,1 ))
HFSSDes ign1
XY Plot 1
ANSOFT
m1
m2
Cur ve In fo
dB(S(1,1))
Setup1 : Sweep
Name X Y
m1 4.3000 -30.9352
m2 2.4500 -29.4630
2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00
Freq [GHz]
1.00
1.25
1.50
1.75
2.00
2.25
2.50
2.75
3.00
VSWR(1)
HFSSDesi gn1
XY Plot 2
ANSOFT
m1
m2
m3
m4
Curv e In fo
VSWR(1)
Setup1 : Sweep
Name X Y
m1 4.3000 1.0576
m2 2.5000 1.0841
m3 3.0000 1.6747
m4 5.4000 1.7440