Design of a Dual-Band Microstrip Patch Antenna for GSM/UMTS/ISM ...

SETIT 2009
5 th International Conference: Sciences of Electronic,
Technologies of Information and Telecommunications
March 22-26, 2009 – TUNISIA
Design of a Dual-Band Microstrip Patch Antenna for
GSM/UMTS/ISM/WLAN Operations
Said GHNIMI*, Adnen RAJHI* and Ali GHARSALLAH*
*Unité de recherche Circuits et Systèmes Electroniques Haute Fréquences, Faculté des sciences de Tunis
said.ghnimi@fst.rnu.tn
adnen.Rajhi@esti.rnu.tn
ali.gharsallah@fst.rnu.tn
Abstract: This paper describes the design of a dual-frequency antenna for GSM and UMTS/LAN/ISM system
applications. A patch antenna with rectangular aperture is designed by using a thick substrate in order to increase the
bandwidth. After this, we have extracted the reflection coefficient of the considered antenna excited by a probe feed and
by optimizing the antenna dimensions and the aperture position. The simulation of this antenna has been made by
advanced design system (ADS) in the band of frequency between 50 Hz and 3.2 GHz, leading to three resonant
frequencies and showing a good impedance bandwidth performance to cover the required bandwidth of the GSM (890–
960 MHz), UMTS (1920–2170MHz) and WLAN/ISM (at 2.45GHz) bands.
Key words: Microstrip patch Antenna, dual-band, GSM, UMTS, ISM and WLAN.
INTRODUCTION
In the last few years the Global System for Mobile
communications (GSM) [RAM 03], the Universal
Mobile Telecommunications System (UMTS) bands
[HOL 01] [SUR 06] [HUB 00], and one of the ISM
bands is at 2.45 GHz which is also the same band for
the Wireless Local Area Network (WLAN) system and
Bluetooth applications have been presented in the
published papers [LIU 07] [LEE 97] [MAL 03].
In the literature, several antennas have been
used in a variety of applications for which new and
more restrictive requirements in the design of the
antenna have been introduced. In particular, for highprecision
GSM, UMTS and ISM/WLAN applications,
few solutions have been proposed by [CHA 02]
[TUN 02] [CIA 03]. Unfortunately, these solutions, it
may easily provide the desired electric characteristics,
but it becomes impractical due to the operational
requirements on size and weight.
The complicated geometry of these various
antennas presents the problem at the levels of the
realization, which require very sophisticated
equipments and a higher cost for the designer, and for
the integration of these antennas in some applications
such as the base station of mobile communication.
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The proposed antenna presents a simple technique;
indeed, the use of a simple substrate of low cost and
larger height allows a good impedance matching; then,
it is necessary to sweep on the dimension of the
antenna L, W and the aperture size, and the
juxtaposition of the feed probe position allows us to
create new resonant frequencies. Once the dimensions
of the resonant antenna are determined, the simulated
coefficient of reflection S11 is extracted.
Furthermore, in order to satisfy the demanded
precision and reliability, for a high performance
proposed antenna a simple modification on the patch
surface has been introduced.
The organization of this paper is as follows,
section 1, the design for the proposed dual-band
rectangular patch antenna is presented, in section 2;
we present results and discussions for the performance
of the proposed antenna. Section 3, contains
conclusions, and recommendations for further studies.
1. Antenna Design
The geometry of the proposed dual-band antenna
is based on the microstrip antenna technique which is
the most popular because of the ease of analysis and
fabrication and having attractive radiation

SETIT2009
characteristics, it consists of a rectangular metallic
patch with a rectangular slot mounted on a grounded
substrate as shown in figure 1.
This microstrip antenna is low-profile
conformable to planar surfaces, simple and
inexpensive to fabricate using the modern printed
circuit technology and it can be used in many
applications such as the phased array for mobile
telecommunication base station. Due to these
advantageous characteristics of the proposed
microstrip antenna, further studies and analysis has
been made in this paper.
Figure 1. Geometry of the dual-band microstrip
patch antenna.
For its simple structure, the new antenna can
be easily simulated by advanced design system (ADS)
simulator. Some useful guidelines for the antenna
design will be discussed as follows.
The structure used in the simulation to
investigate the due to RF pulses is showed in Figure. 1
where a simple microstrip patch antenna was made
with plexy-glass material (εr =2.55), the thickness of
the patch is assumed negligible and the height h of the
substrate is taken equal to 2.5 cm.
The effects of the medium and the fringing
fields at each end of the patch are accounted for by the
effective relative dielectric constant, εeff, and the edge
extension, ∆L, being the effective length to which the
fields fringe at each end of the patch. The following
effective dielectric constant formula proposed is used
in equation 1
1
−
2
ε r + 1 ε r −1
h
ε eff = + ( 1+
12 ) (1)
2 2 W
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With
∆L
=
h
And
0,
412
( ε
( ε
r
eff
eff
W
+ 0,
3)(
+ 0,
264)
h
W
− 0,
258)(
+ 0,
8)
h
r
eff
(2)
λ C c0
L = = =
(3)
2 2 f 2 f ε
In general, the resonant frequency of rectangular
patch antennas is calculated by using resonant length
transmission line or cavity models, together with
equations for the effective dielectric constant and edge
extension from the literature. The resonant frequency
fmn of a rectangular patch of width W and length L,
both comparable to λs /2, where λs is the wavelength
in the substrate, is given by
f
mn
2
2
c ⎡⎛
⎞ ⎤
0 m ⎛ n ⎞
= ⎢
⎜
⎟ +
⎜
⎟ ⎥
2 ε ⎢⎣
⎝ L
eff e ⎠ ⎝We
⎠ ⎥⎦
(4)
Where εeff is the effective relative dielectric
constant for the patch, m and n take integer values,
and Le and We are the effective dimensions.
L e
The effective length Le can be defined as follows:
= L + 2 ∆L
(5)
In order to determine the resonant frequency, the
band of use of this antenna is defined by:
Fmax
− Finf
B(%)
= 100
(6)
F
r
The dimensions of the proposed patch are the
width W= 8cm and the length L=8.55 cm, with a
copper plane on one side; in the patch, a slot is
designed with a length equal to y2-y1 = 4cm and a
width x0 = 0.4cm, the distance between the probe feed
and the slot is d=y1-y0. The coaxial feed was excited
by RF source with impedance of 50 Ohms, and the
frequency band of analysis ranges the antenna from
electrically short at the lowest frequency to electrically
long at the highest frequency.

SETIT2009
2. Results and discussion
A prototype of the antenna has been tested by
ADS simulator, with the above given geometrical
dimensions of the patch. The simulation returns loss of
this antenna is presented in figure 2 for three different
distances between the probe feed and the slot edge
(d1=0.01mm d2=1cm, d3=2cm).
Return loss[dB]
0
-5
-10
-15
-20
-25
-30
-35
-40
-45
GSM band
S11
d1
d2
d3
UMTS band
0.5 1 1.5 2 2.5 3
x 10 9
Frequency[Hz]
Figure 2. Comparisons of the simulated return loss of
the microstrip patch antenna for different distances
(d1=0.01mm d2=1cm, d3=2cm).
From this simulation we found dual bands, the first
is around a resonant frequency Fr1 and the second
band can be considered as around two resonant
frequencies (Fr2, Fr3), and it demonstrates that a
good input match has been obtained for both the
GSM/UMTS bands and LAN/ISM operations. The
optimal proposed antenna is for d2=1cm which covers
the required bandwidth respectively of the GSM 900,
UMTS 2000 bands and ISM/WLAN 2450 operations.
For GSM 900, a wide operating frequency range of
890 to 995 MHz is obtained, and the impedance
bandwidth determined from -10 dB return loss can
reach 105 MHz (or 11.37 % referenced to 923 MHz).
For UMTS 2000, a much wider operating frequency
range of 1900 to 3100 MHz can be obtained, and the
impedance bandwidth determined from -10 dB return
loss can even reach 1200 MHz (or 55.88 % referenced
to 2150 MHz).
The simulation results are summarized in the
table’s 1-3.
Type
d’antenne
Central
d1 d2 d3
frequency
Fr1GHz
0.921 0.923 0.921
BP [%] 10.74 11.37 9.66
Table 1. Bandwidth around Fr1
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Table 1, present the bandwidth around the first
Fr1 resonance frequency and it is noted that the
resonant frequency Fr1 and the bandwidth are almost
the same one for the different distances d.
Table 2. Bandwidth around Fr2
Table 3. Bandwidth around Fr3
Table 2 and Table 3, present respectively the
bandwidth around the resonance Fr2 and Fr3
frequency, and it is noted that the bandwidth depends
on the distance d. Indeed, one notes for d= 1cm the
microstrip patch antenna present a large bandwidth
and more performance around resonance frequency.
By analyzing the ADS Simulation results of the
reflection coefficient of the proposed antenna, we can
conclude that the antenna has three resonant
frequencies (Fr1, Fr2, and Fr3); and for the different
distances, the frequency Fr1 is almost the same, but
the other frequencies Fr2 and Fr3 changes by
changing the distance d.
The resonant frequency Fr1 given by (7) can be
calculated from the fundamental TM10 mode of the
patch antenna with the dimensions (W = 8cm, L =
8.55 cm), to intend GSM band.
F
r1
Type
d’antenne
Central
d1 d2 d3
frequency
Fr2GHz
2.25 2.15 2.16
BP [%] 47.55 55.88 28.37
Type
d’antenne
Central
d1 d2 d3
frequency
Fr3GHz
2.74 2.97 2.85
BP [%] 39.05 40.4 17.54
c0
= f10
=
(7)
2L
ε
e
eff
In order to investigate the dependence at the
second resonant frequency Fr2 and at the third
resonant frequency Fr3 according to the different
values of d which represent the distance between the
probe feed and the slot, figure.3 and figure.4 are
presented to explain this dependence.

SETIT2009
Fr2[GHz]
Fr3[GHz]
2.28
2.26
2.24
2.22
2.2
2.18
2.16
2.14
0 0.2 0.4 0.6 0.8 1
d[cm]
1.2 1.4 1.6 1.8 2
3
2.95
2.9
2.85
2.8
2.75
Figure 3. Effect of the distance d on resonance
frequency Fr2
2.7
0 0.2 0.4 0.6 0.8 1
d[cm]
1.2 1.4 1.6 1.8 2
Figure 4. Effect of the distance d on resonance
frequency Fr3
Figure.3 and Figure.4 show how the both
resonances frequencies Fr2 and Fr3, depend
respectively from the distance d between the slot and
the probe feed, indeed, these variations of Fr2 and Fr3
have inverse behaviors if Fr2 increases then Fr3
decreases and vice versa.
3. Conclusion
The main quality of the proposed antenna is that it
allows an effective design maintaining all the
advantages of microstrip antennas in terms of size,
weight and easy manufacturing. Moreover, this
antenna has a good effectiveness on the totality of the
three covered respectively, GSM, UMTS and
WLAN/ISM frequency bands. This work has to be
studied further to have more precise expressions for
- 4 -
the dependence of Fr2 and Fr3 with the distance d
between the slot and the feed probe.
REFERENCES
[RAM 03] Rammal, M.; Abou Chahine, S.; Fadlallah, N,
“An improved FDTD design of a wideband GSM patch
antenna”, Proceedings of the Twentieth National Radio
Science Conference, March 2003, pp.B17 - 1-5.
[HOL 01] H. Holma and A. Toskala, “WCDMA for UMTS:
Radio Access for Third Generation Mobile
Communications”, John Wiley & Sons, New York,
2001.
[SUR 06] E. Surducan, D.S.Iancu, V.Surducan, J.Glossner,
“Microstrip composite antenna for multiple
Communication protocols”, International Journal of
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[HUB 00] J.F. Hubner, D. Weiler, H. Brand, “UMTS, the
Mobile Multimedia Vision for IMT-2000: A Focus on
Standardization”, IEEE Communication Magazine,
September 2000, pp. 129-136.
[LIU 07] Juan Liu, Jing Xia, Gang Wang,“A Dual-Band
Microstrip-Fed Bow-Tie Antenna for GSM/CDMA and
3G/WLAN”, IEEE 2007 International Symposium on
Microwave, Antenna, Propagation, and EMC
Technologies For Wireless Communications, Aug. 2007,
pp.504-507.
[LEE 97] K.F. Lee, et al., “Experimental and Simulation
Studies of the Coaxially Fed U-slot Rectangular Patch
Antenna ”, IEE Proceedings- Microwave Antennas and
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[MAL 03] Malisuwan, S.; Charoenwattanapom, M.;
Huvanandana, S.; Rosesukon, K., “Design of Microstrip
Antenna for Bluetooth and WAN Applications y
Applying Modified Smithchart Representation”, IEEE
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[CHA 02] CHANG, F.S., YEH, S.H., and WONG, K.L.:
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(11), pp. 499–500.
[TUN 02] H. C. Tung and K. L. Wong, “Dual-Band
Inverted-L Monopole Antenna for GSM/DCS Mobile
Phone,” in 2002 IEEE Antennas Propagat. Soc. Int.
Symp. Dig., San Antonio, Texas, USA, vol. 3, pp. 30-33.

SETIT2009
[CIA 03] P. CIAIS, R. STARAJ, G. KOSSIAVAS, C.
LUXEY, “Antenne miniature quadri-bande
GSM/DCS/PCS/UMTS ”, 13émes Journées Nationales
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