circularly polarized triangular ring slot antenna with dgs for harmonic suppression ·...
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CIRCULARLY POLARIZED TRIANGULAR RING SLOT
ANTENNA WITH DGS FOR HARMONIC SUPPRESSION
Ch. Hanusha
M.Tech Student, Dept. of ECE
Acharya Nagarjuna University
Guntur, India.
Email:chittelahanusha@gmail.com
K. Lakshmi Bhavani
Assistant Professor, Dept. of ECE
Acharya Nagarjuna University
Guntur, India.
Email:konduribhavani@gmail.com
Abstract:
In this paper a triangular ring slot antenna is
proposed which is designed to operate at 5.5GHz.
Apart from this fundamental mode, additional
harmonics are produced. These harmonics are
suppressed by integrating an inverted U-shaped slot
into the antenna. This defected ground structure is
used to achieve harmonic suppression at 11GHz and
15GHz. Further a tilted slot is embedded in the ring
slot antenna to produce circular polarization
Keywords: Defected ground structure (DGS),
Circular polarization, and Triangular ring slot
antenna.
1. Introduction:
The radio frequency communication device
is a combination of active and passive elements. The
power amplifier and low noise amplifier constitute
the active elements while antenna and filter constitute
the passive elements [1] [2]. The size of the RF
circuit can be minimized by integrating the antenna
with the power amplifier. This active integrated
antenna design poses the problem of reducing the
power amplifier efficiency due to electromagnetic
interference caused by higher order modes excited by
the antenna [3].
To avoid this problem, the higher order
modes or Harmonics which are repeated at multiples
of fundamental frequency are to be suppressed [4].
Thus it is ideal to use a low pass filter along with the
antenna. Various methods to suppress the unwanted
modes include loading of additional tuning stubs and
multiple shorting pins into a patch antenna. These
methods were proved to be inefficient in terms of
suppressing band width. In order to obtain wide
suppressing band width, defected ground structure
can be used [5] [6]. This technique involves
integration of various types of slots with the patch
Antenna. In this paper an inverted U-shaped slot is
loaded on the triangular ring slot antenna [7] [8]. The
satellite communications use circular polarization
since the ionosphere tends to change the polarization
of the transmitted wave
. This is a problem, if linear polarization is
used. In circular polarization the electric field is
passing wave does not change strength but only
changes direction in a rotary manner. The use of
circular polarization at each end of link reduces
fading and flutter.
2.Antenna design:
The satellite communication system uses the
C-band with frequency range from 4GHz-8GHz.
Hence the antenna designed must be able to operate
in this frequency range.
The operating frequency selected for the
design is 5.5GHz. And the dielectric material is FR4
which has a dielectric constant of 4.4.
The side of the inner triangle is t1= 10mm and
Side of the outer triangle is t2=14mm is calculated by
the formulae
Circle radius (a) = side of the triangle (t)/sqrt (3),
a1= inner circle radius and
a2 = outer circle radius.
0F =r
r
aa
c
ξ
ξ 1.
)21(
+
+∏.
Where 0F = operating frequency,
rξ = relative permittivity of the substrate,
c= velocity of light,
International Journal of Scientific & Engineering Research, Volume 6, Issue 5, May-2015 ISSN 2229-5518
1798
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Fig: 1. C-Band antenna without defected ground
structure
The harmonics obtained for this antenna are
suppressed by using defected ground structure
(DGS). The antenna with defected ground structure is
shown below.
Fig: 2. proposed antenna with defected ground
structure
3.Circularly polarized ring slot antenna:
To achieve circular polarization for the
triangular ring slot antenna mentioned above, a tilted
slot is cut as shown in below figure.
Fig: 3. proposed circularly polarized antenna
4.Simulation:
The simulation of patch antenna is done
using HFSS (high frequency structural simulator)
version 14.0. It uses finite element method (FEM) for
solving electromagnetic structures and designs of
antennas, RF electronic circuit elements such as
filters and transmission lines.
5.Results and analysis:
For this C-band triangular ring slot antenna
the Return loss of -23.3db is obtained at 5.5GHz. The
harmonics are obtained at 11GHz, 15GHz.
2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00Freq [GHz]
-37.50
-25.00
-12.50
0.00
dB
(S(1
,1))
HFSSDesign2XY Plot 1 ANSOFT
m1
m2
m3
Curve Info
dB(S(1,1))Setup1 : Sw eep
Name X Y
m1 5.9000 -23.3702
m2 11.4000 -37.0947
m3 15.1000 -10.9662
Fig: 4. Return loss without DGS
The harmonics 12GHz and 15GHz are
suppressed by using defected ground structure. The
return loss curve for defected ground structure
antenna is shown below. The return losses at 12GHz
International Journal of Scientific & Engineering Research, Volume 6, Issue 5, May-2015 ISSN 2229-5518
1799
IJSER © 2015 http://www.ijser.org
IJSER
and 15GHz are reduced to 7.6db and 8.21 db
respectively.
2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00Freq [GHz]
-22.50
-20.00
-17.50
-15.00
-12.50
-10.00
-7.50
-5.00
-2.50
0.00
dB
(S(1
,1))
HFSSDesign2XY Plot 1 ANSOFT
m1
m2m3
Curve Info
dB(S(1,1))Setup1 : Sw eep
Name X Y
m1 5.4000 -22.1943
m2 12.0000 -7.6143
m3 15.5000 -8.2146
Fig: 5. return loss of DGS antenna
The polarization is observed to be linear
from the axial ratio curve shown below.
0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00Theta [deg]
10.00
20.00
30.00
40.00
50.00
60.00
70.00
dB
(Ax
ialR
ati
oV
alu
e)
HFSSDesign2XY Plot 9 ANSOFT
m1
Curve Info
dB(AxialRatioValue)Setup1 : LastAdaptiveFreq='5.5GHz' Phi='0deg'
dB(AxialRatioValue)Setup1 : LastAdaptiveFreq='5.5GHz' Phi='90deg'
Name X Y
m1 0.0000 56.4202
Fig: 6. axial ratio curve of DGS antenna
3D-polar plot:
The total gain of 3.74dB is observed from
3D-polar plot is shown in below figure.
Fig: 7. 3D-polarplot
Circularly polarized ring slot antenna:
The tilted slot which is cut on the triangular
ring slot antenna gives circular polarization. The
axial ratio measured is found to be 2.69db.
0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00Theta [deg]
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
45.00
dB
(Ax
ialR
ati
oV
alu
e)
HFSSDesign2XY Plot 3 ANSOFT
m1
Curve Info
dB(AxialRatioValue)Setup1 : LastAdaptiveFreq='5.5GHz' Phi='0deg'
dB(AxialRatioValue)Setup1 : LastAdaptiveFreq='5.5GHz' Phi='90deg'
Name X Y
m1 0.0000 2.6915
Fig: 8. axial ratio of circularly polarized antenna
3D-polar plot and radiation pattern:
The total gain of 3.20 dB is observed from
3D-polar plot as shown in figure.9. The simulated
radiation pattern of the antenna at 5.5GHz is shown
in figure.10.
International Journal of Scientific & Engineering Research, Volume 6, Issue 5, May-2015 ISSN 2229-5518
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Fig: 9. 3D-polar plot
-5.60
-3.20
-0.80
1.60
90
60
30
0
-30
-60
-90
-120
-150
-180
150
120
Radiation Pattern 1
Fig: 10. Radiation pattern
Conclusion:
A U-shaped defected ground structure is
designed and loaded onto the triangular ring slot
antenna for harmonic suppression. The higher order
modes at 11GHz and 15GHz are effectively
suppressed. Along with this, circular polarization is
achieved by the use of a tilted slot on the triangular
patch. The Axial ratio thus observed is 2.69dB.
References:
[1] K. Chang, R. York, P. Hall, and T. Itoh, “Active
integrated antennas,”IEEE Trans. Microw. Theory
Tech., vol. 50, no. 3, pp. 937–944, Mar.2002.
[2] D. Segovia-Vargas, D. Castro-Galán, L. E.
Garc´ıa-Muñoz, and V.González-Posadas,
“Broadband active receiving patch with resistive
equalization,” IEEE Trans. Microw. Theory. Tech.,
vol. 56, no. 1, pp.56–64, Jan. 2008.
[3] V. Radisic, Y. Qian, and T. Itoh, “Novel
architectures for high-efficiency amplifiers for
wireless applications,” IEEE Trans. Microw. Theory
Tech., vol. 46, no. 11, pp. 1901–1909, Nov. 1998.
[4] V. Radisic, S. T. Chew, Y. Qian, and T. Itoh,
“High efficiency power amplifier integrated with
antenna,” IEEE Microw. Guided Wave Let. vol. 7, no.
2, pp. 39–41, Feb. 1997.
[5] Y. J. Sung, M. Kim, and Y. S. Kim, “Harmonics
reduction with defected ground structure for a micro
strip patch antenna,” IEEE Antennas Wireless
Propag. Let. vol. 2, pp. 111–113, 2003.
[6] S. Biswas, D. Guha, and C. Kumar, “Control of
higher harmonics and their radiation in micro strip
antennas using compact defected ground structures,”
IEEE Trans. Antennas Propag., vol. 61, no. 6,
pp.3349–3353, Jun. 2013.
[7] D. H. Choi, Y. J. Cho, and S. O. Park, “A
broadband slot antenna with harmonic suppression,”
Microw. Opt. Technol. Let., vol. 48, no. 10,pp. 1984–
1987, Oct. 2006.
[8] J. S. Park, J. H. Kim, J. H. Lee, S.H. Kim, and S.
H. Myung, “A novel equivalent circuit modeling
method for defected ground structure and its
application to optimization of a DGS low pass filter,”
in IEEE Int. Microw. Symp. Digest, 2002, vol. 1, pp.
417–420.
[9] Bahi I J & Bharta P, micro strip antenna(artech
house, Massachusetts, USA),1980.
[10] lu jui-han & wong kin lu, single- feed circularly
polarized equilateral- triangular micro strip antenna
with a triangle stub, IEEE trans antenna & propag
(USA), 48 (2000) 1869.
International Journal of Scientific & Engineering Research, Volume 6, Issue 5, May-2015 ISSN 2229-5518
1801
IJSER © 2015 http://www.ijser.org
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