International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, Volume 1, Issue 2, December 2011)
A Compact Planar Multiband Antenna For WLAN: Design,
Simulation and Results
Akhilesh Kumar1, Charu Tyagi2, Rekha Rani3 , Ritika Tripathi4
1
Depatrment of Electronics & Communication, Rajkumar Goel Institute of Technology For Women ,U.P.(India)
1
akhilesh48@gmail.com
Charutyagi24@rediffmail.com
2
In order to satisfy the IEEE 802.11 WLAN standards in
the 2.4 GHz (2400–2484 MHz)/5.2 GHz (5150–5350
MHz)/5.8 GHz (5725–5825 MHz) operating bands and
the worldwide interoperability for microwave access
(WiMAX) 2.5/3.5/5.5 GHz(2500-2690/3400-3690/52505850 MHz) bands, multi-band antennas with low cost,
compact size, easy fabrication and higher performance are
required. Several dual-band antennas
for WLAN
applications were presented [1]–[5]. However, none of the
above available designs can achieve a dual-band response
with sufficiently large bandwidth to additionally cover the
whole WiMax bands.
Abstract-- With the rapid development of wireless
communication systems, the multiple separated frequency
bands antenna has become one of the most important
circuit elements and attracted much interest. In order to
satisfy the IEEE 802.11 WLAN standards in the 2.4 GHz
(2400–2484 MHz)/5.2 GHz (5150–5350 MHz)/5.8 GHz
(5725–5825 MHz) operating bands and the worldwide
interoperability for microwave access (WiMAX) 2.5/3.5/5.5
GHz (2500–2690/3400–3690/5250–5850 MHz) bands,
various antennas for wide band operation have been
studied for communication and radar systems. The design
achieves a good input impedance match and linear phase of
S11 throughout the pass band (1.5–7 GHz and-10 dB
criterion for impedance bandwidth). Various bands are
1.96 GHz, 3 GHz, 5GHz. The gain of the antenna at
resonant frequencies is >4.6 dBi. The maximum directivity
of the antenna is 8.5dBi and the VSWR is between 1 and 2.
The bandwidth of the antenna is 200 MHz, 1100 MHz, 2030
GHz bands respectively. This antenna is suitable for
applications in ICMS, DECT, UMTS, Bluetooth and
WLAN systems. Because of linear phase and good
impedance match, with some further optimization and
manufacturing aspect, this antenna can serve in UWB and
wireless USB applications.
Keywords—multiband antenna, monopole antenna, WLAN,
U slot antenna, WiMAX , Triangular Patch, CPW Feed.
I. INTRODUCTION
The current upsurge in wireless communication
systems has forced antenna engineering to face new
challenges, which include the need for small-size, highperformance, low-cost antennas.
Figure.1. Geometry of proposed antenna with infinite
ground plane
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International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, Volume 1, Issue 2, December 2011)
A multiband-wideband assembled monopole antenna
Therefore, the initial antenna design is provided by
with a small size is presented in this communication. The
these design equations. Furthermore, accurate design for
proposed antenna can generate four resonant frequencies
the proposed antenna need to be adjusted and optimized
which are formed into three wide bands centered at about
using electromagnetic simulation software (such as IE3D).
1.96 GHz, 3.04 GHz and 5 GHz to cover all the
To excite the antenna, a 50-CPW transmission line,
1.9/2.4/5.2/5.8 GHz GPS & WLAN operating bands and
having a signal strip of width W1 and a gap of g distance
the 2.5/3.5/5.5 WiMAX bands. With multi-wideband
between the signal strip and the side plane, is used. The
operation achieved in this design, the assembled
proposed antenna geometry is placed on finite ground
monopole antenna requires a small size of 30 X 50mm2.
plane of 50 X 50 mm . To enhance the antenna parameters
The antenna also shows good dipole-like radiation
a rectangular slots of 12 x 8 mm is cut on the opposite
characteristics with small cross-polarization level and
edges of the ground plane as shown in figure 2.
moderate gain over the operating bands, which is
The design of the proposed antenna follows the
attractive for practical application in the WLAN/WiMAX
described guidelines followed by the optimization with the
communication gadgets.
software IE3D. In the design, the antenna is printed on a
1.6 mm thick FR4 substrate of dielectric constant 4.4 and
loss tangent 0.0245. The rectangular proximity patch and
II. PROPOSED ANTENNA DESIGN
annular slot is employed to generate the first mode at 1.9
The geometry of the proposed monopole antenna is
GHz , U-shaped monopole is employed to generate the
shown in Figure.1.The antenna is formed by an equilateral
first resonant mode at about 2.5 GHz for lower band
triangular monopole and a modified U-shaped and
operation, while the triangular monopole is employed to
rectangular monopole, and is fed by a CPW microstrip
create a fundamental mode at about 3.6 GHz for upper
feed line. In order to get a compact antenna size for the
band operation. Values of the design parameters shown in
design, the U-shaped and rectangular monopole is placed
Figure. 1 and Figure 2. calculated using the presented
outside the triangular monopole.
method and optimized using IE3D are L=15 mm, L1=19
The dual-band performance of the proposed antenna
mm L2=16 mm , L3 = 12 mm , L4= 6.5 mm, L5= 35 mm
is obtained from the dual resonant monopoles of
, W= 12mm , W1= 3mm, W2=1.5mm, W3= 8mm, P1=
different dimensions. In the geometry, the resonant path
9mm, P2 = 9mm, S =1.5mm, g = 0.5 mm .
length ( L11= S + L3 + L1 )and (L22 = S + L4 + L2) of
the U-shaped , rectangular monopole and the triangular
monopole are set close to quarter-wavelength at the their
fundamental resonant frequencies, and can be calculated
from the following equations:
L11 = c / 4 f1 √ εre
--- (1)
L22 = c / 4 f2 √ εre
----(2)
εre = (εr +1) / 2
----(3)
where c is the speed of light, εre is the relative
permittivity of the substrate, f1 and f2 denote the
fundamental resonant frequencies of the U-shaped and
square shaped monopole and triangular monopole
respectively.
Figure.2. Geometry of proposed antenna with finite ground
Plane
However, the design (1) to (3) are only suitable for the
single rectangular ,U-shaped monopole or the triangular
monopole, without considering the mutual coupling
between the monopoles.
18
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, Volume 1, Issue 2, December 2011)
III. RESULT AND DISCUSSION
According to the design dimensions given above, the
tri-wide- band antenna was designed and simulated on
IE3D.The simulated reflection coefficient of the antenna
is shown in Fig. 5. It is seen from the results that two
wide and one narrow operating bands centered at about
1.9 GHz, 3 GHz a n d 5 GHz and are excited with
good impedance matching. The -10dB impedance
bandwidths for the lower and upper bands reach
200MHz (1.84–2.04 GHz), 1100 MHz (2.40–3.50 GHz)
and 2030 MHz ( 4.36-6.39 GHz) respectively, which are
able to cover the 2.4/5.2/5.8 GHz WLAN bands and
2.5/3.5/5.5 GHz WiMAX bands.
To demonstrate the effect of the triangular
monopole and the U-shaped monopole on generating the
antenna’s lower and upper bands, the simulated reflection
coefficient ( in Figure 6.), Current distribution (in Figure
5), Directivity (in Figure 9), Gain (in Figure7) of the
assembled antenna are presented. It is seen that first
mode at about 1.9 GHz, second mode at about3GHz
and a second mode at about 5.2 GHz are obtained with
return loss of -14.5, -33.95 and -38.68 respectively with a
peak gain of 8.5dBi and peak directivity of 9.5dBi .
Figure.6. Simulated reflection coefficient (S11 in dB)
characteristics of proposed planar antenna
Figure.7. Gain characteristic of Proposed antenna
Figure.5.Current Distribution of Proposed antenna
Figure.8. Efficiency of Proposed antenna
19
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, Volume 1, Issue 2, December 2011)
Figure:9. Directivity characteristic of Proposed antenna
(b)
Figure10 : Axial ratio of proposed antenna
(c)
Figure.11 .Azimuth radiation pattern of proposed
antenna at different band Frequencies
IV. CONCLUSION & FUTURE WORK
A compact antenna for multi-wideband operation has
been proposed. The antenna has a simple structure and is
easy to be printed on FR4 substrate with small area of
about 50 x 50 mm. In addition, although the antenna shows
a simple structure and compact size it can generate three
broad bands centered at about 1.9 GHz , 3 GHz and 5
GHz to cover the 2.4/5.2/5.8 GHz WLAN bands and the
2.5/3.5/5.5 WiMAX bands. The antenna shows good
dipole-like radiation characteristics with moderate gain
over the operating bands, which are attractive for practical
application in the WLAN/ WiMAX communication
devices.
(a)
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International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, Volume 1, Issue 2, December 2011)
In future , the gain and bandwidth of antenna can be
enhanced by using parasitic patch, L probe feed or by
introducing an air gap between ground plane and
dielectric[11] . By using some different fractal geometries
this antenna can also be used for lower band of
frequencies with size miniaturization [10].
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