The document summarizes the design and simulation of a T-shaped fractal microstrip patch antenna for microwave band applications. The antenna was designed using a fractal technique with a scaling factor of 1/3 at each iteration to achieve multiband operation. Simulation results showed resonances at 2.4 GHz, 6.8 GHz, 8 GHz, 10.8 GHz, 12.2 GHz and 15.4 GHz with bandwidths ranging from 230 MHz to 2 GHz. The antenna exhibited VSWR less than 2 and gain higher than other resonant frequencies at 2.4 GHz, 8 GHz and 15.4 GHz. The fractal antenna design achieved size reduction and multiband performance making it suitable for applications such as wireless communications.
Study on Air-Water & Water-Water Heat Exchange in a Finned Tube Exchanger
T-Shape Fractal Antenna for Microwave Applications
1. Int. Journal of Electrical & Electronics Engg. Vol. 2, Spl. Issue 1 (2015) e-ISSN: 1694-2310 | p-ISSN: 1694-2426
NITTTR, Chandigarh EDIT -2015 86
T- Shape Antenna Design for Microwave
Band Applications
Shalini Bhickta
Electronics & Communication Engineering Department
AP Goyal Shimla University, Shimla, H.P
bhicktashalini25589@gmail.com
Abstract—It’s been studied fractal antennas shows promising
future. There are numerous kinds of antenna, the thirst for
excelling in this area is ever increasing. In this paper a Fractal
based Antenna is designed to achieve reduced size and
multiband. Fractal antenna is simulated using EM wave
simulator like HFSS (High frequency structured simulator)
and is designed and developed for multiple applications. The
proposed antenna is experimentally realized using FR Epoxy
substrate with dielectric constant 4.4 and thickness h= 1.56
mm with coaxial feeding. The patch has the dimensions of 2.5
cm 2.5 cm. An experimental result of this antenna shows
multiband characteristics having resonances at frequencies
such as 2.4 GHz , 6.8 GHz, 8 GHz, 10.8 GHz, 12.2 GHz,15.4
GHz with bandwidth of 230 MHz, 2 GHz, 600 MHz, 870 MHz
and 2 GHz respectively. Further VSWR is also studied in this
paper.
Index Terms—Fractal, Microstrip, Space filling, coaxial
feed.
I. INTRODUCTION
Antennas has till now proved as life to wireless
communication systems. Future of such antenna is in there
compact sizes, good antenna gain. There are many kinds of
antenna that shows promising applications in various fields
[1]. Micro strip patch antennas is one of them, they are
simple, less expensive and low profile antennas. Several
geometries have been explored with numerous
characteristics to obtain desired results. Fractal nature of
antenna sets this in different category of antenna. This
paper shows the special type of antenna using Fractal
technique, every iteration follows preceding iteration [2].
Fractal antenna can be simulated for much iteration
until the desired result is achieved, they are multiband
antenna. The concept of fractal antenna helps in designing
multiband antennas [3]. . The two main properties of
fractal antenna are self similarity in their structure i.e. a
fragmented geometric shape that can be subdivided in
parts, each of which is a reduced size copy of the whole
[4]. Second is its space filling property which enable
miniaturization of antenna for very this reason fractal
antenna are very compact or multiband or wideband and
have useful application in cellular telephone and
microwave application [5]. Fractal structure is generated
using Integrated Fractal system algorithm which uses a
scaling factor [6] expressed as,
= (1)
Where, = scaling factor ratio
h = height of iterated antenna (T-shape)
n = iteration number
II. ANTENNA DESIGN
The proposed antenna is a multiband antenna based on
the square fractal antenna. This structure is designed with
space filling property of fractal antenna. The size of the
antenna increases as the resonant frequency decreases.
Therefore to operate antenna on same frequency fractal
antennas are designed smaller in size. In this design the
size of the antenna is 2.5 X 2.5 cm. The scaling factor for
each of the iteration is taken as one – third (1/3) to
maintain the perfect geometry symmetry.
The first order geometry of T shape is of dimension (1.
35 cm X 1.35) cm, then two T shape (0.45 X 0.45 ) cm size
are included on top of the previous T which forms the
second order of geometry, third order geometry includes
T-shape of (0.15 X 0.15) cm size. The conductor is
copper clad, in terms of wavelength size of the proposed
antenna is (where is the wavelength at lowest resonant
frequency). Fig.1 shows the detailed structure of T-shaped
fractal antenna after its third proposed iteration geometry.
The antenna is fed by coaxial line from a wave-port.
The antenna is fabricated on FR4 Epoxy of relative
permittivity 4.4 and the thickness of substrate is t=1.56
mm. Mathematically, resonating frequency of the antenna
is calculated [7,8] using the equation (2)
= ∈
(2)
c = speed of light, = resonant frequency
∈ = Effective permittivity and it is calculated using
equation (3).
∈ =
∈
+
∈
( )
(3)
III. RESULTS AND DISCUSSION
A. Simulation Results
The proposed antenna is simulated on High Frequency
Structured Simulator (HFSS), characteristics of proposed
antenna have been analyzed on several parameters like
2. Int. Journal of Electrical & Electronics Engg. Vol. 2, Spl. Issue 1 (2015) e-ISSN: 1694-2310 | p-ISSN: 1694-2426
87 NITTTR, Chandigarh EDIT-2015
Fig.1 Geometry of proposed antenna
VSWR, return loss, total gain and radiation pattern. Fig.2
gives the VSWR (Voltage standing wave ratio) for the
proposed antenna which shows promising results of
VSWR < 2.
Fig.3 shows the return loss of the proposed antenna
i.e. -14.53 dB, -21.31 dB, -24.14 dB, -16.69 dB, -21.83
dB, -16.7 dB and -19.836 dB respectively with
bandwidth of 230 MHz, 2 GHz, 600 MHz, 870 MHz
and 2 GHz at the resonant frequencies. The figure
depicts that, this antenna is multiband
Fig.2. VSWR (Voltage standing wave ratio) of antenna
applied at frequencies 2.4 GHz, 6.8 GHz, 8 GHz,
10.8 GHz,.2 GHz, and 15.4 GHz since in these
frequencies the simulated coaxial fed return loss S11 <
−10 dB.
0.00 2.50 5.00 7.50 10.00 12.50 15.00 17.50 20.00
Freq[GHz]
0.00
2.50
5.00
7.50
10.00
12.50
15.00
17.50
20.00
22.50
25.00
27.50
30.00
dB(VSWR(1))
HFSSDesign1XYPlot2 ANSOFT
m1
m2
m3
m4
m5
m6
CurveInfo
dB(VSWR(1))
Setup1:SweepName X Y
m1 2.4000 3.2894
m2 6.8000 1.4967
m3 7.5000 2.1598
m4 8.1000 1.1745
m5 10.8000 2.5600
m6 12.1000 1.3493
3. Int. Journal of Electrical & Electronics Engg. Vol. 2, Spl. Issue 1 (2015) e-ISSN: 1694-2310 | p-ISSN: 1694-2426
NITTTR, Chandigarh EDIT -2015 88
Fig.3. Return loss of the proposed antenna design
Fig.4 shows the total field gain of the antenna. The
result at 2.4 GHz, 8GHz & 15.4 GHz resonant
frequencies gives better total gain as compared with
other resonant frequencies at Phi = 0 degree & theta all.
VSWR of the geometry at different iterations is studied
and shown as graphical representation of VSWR w. r. t
the resonant frequencies of the antenna in Fig.5. Here,
the VSWR of the final iterated geometry is better as
compared to the VSWR of first & second iteration of the
T-shape antenna.
Fig.4 Total gain of the antenna
B. Comparison of Simulated VSWR vs. Frequency
Fig.5. VSWR vs. FREQUENCY
The azimuth and elevation radiation patterns are
simulated in all the resonant frequencies. Fig. 6 & 7
shows the simulated Elevation & azimuth radiation
pattern of the antenna. The simulation has been carried
out at resonances as observed in the S11 measurement.
0.00 2.50 5.00 7.50 10.00 12.50 15.00 17.50 20.00
Freq [GHz]
-25.00
-20.00
-15.00
-10.00
-5.00
0.00
dB(S(1,1))
HFSSDesign1XY Plot 1 ANSOFT
m3
m4
m5
m1
m6
m2
Curve Info
dB(S(1,1))
Setup1 : Sw eep
Name X Y
m1 2.4000 -14.5576
m2 6.8000 -21.3158
m3 8.0000 -24.1466
m4 10.8000 -16.6947
m5 12.2000 -21.8308
m6 15.4000 -16.7081
-100.00 -75.00 -50.00 -25.00 0.00 25.00 50.00 75.00 100.00
Theta[deg]
-10.00
-5.00
0.00
5.00
10.00
15.00
dB(GainTotal)
HFSSDesign1XYPlot5 ANSOFT
CurveInfo
dB(GainTotal)
Setup1: Sweep
Freq='2.4GHz'Phi='0deg'
dB(GainTotal)
Setup1: Sweep
Freq='8GHz'Phi='0deg'
dB(GainTotal)
Setup1: Sweep
Freq='15.4GHz'Phi='0deg'
0
1
2
3
4
5
6
7
2.4 6.8 8 10.8 12.2 15.4
VSWR VSWR v.s FREQUENCY
VSWR of
entire
Geometry
VSWR of
first
iteration
VSWR of
second
iteration
FREQUENC
Y
4. Int. Journal of Electrical & Electronics Engg. Vol. 2, Spl. Issue 1 (2015) e-ISSN: 1694-2310 | p-ISSN: 1694-2426
89 NITTTR, Chandigarh EDIT-2015
Fig.6 Elevation pattern of the proposed antenna. Fig.7 Azimuth pattern of the proposed antenna.
IV. CONCLUSION
The proposed T-shaped fractal microstrip patch antenna
is simulated over High Frequency Structure Simulator
(HFSS) software as a simulation tool. Various
characteristics like total field gain, return loss, radiation
pattern and VSWR has been obtained from the simulation
results. The antenna design can work in different
microwave bands according to the results. This paper also
depicts as we increase the number of iterations the gain and
VSWR at different resonant frequencies gets better. The
proposed antenna design finds applications in X-band,
Radars, Medical, Satellite & WLAN communications.
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