H shape defected ground structure dgs- embedded square patch antenna
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This document summarizes a research paper that designed and simulated a microstrip patch antenna with an H-shaped defected ground structure (DGS) for bandwidth improvement and miniaturization. Key findings include: 1) A conventional square patch antenna was designed to resonate at 2.36GHz. 2) An H-shaped DGS was embedded in the ground plane of the antenna to perturb the current distribution and affect the input impedance. 3) Simulations showed the DGS antennas resonated at lower frequencies than the conventional antenna, with impedance bandwidth improvements up to 500MHz and size reductions up to 65.51%. 4) Radiation patterns of the DGS antennas remained nearly omn
![International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online), Volume 6, Issue 1, January (2015), pp. 73-79 © IAEME
73
H-SHAPE DEFECTED GROUND STRUCTURE (DGS)
EMBEDDED SQUARE PATCH ANTENNA
Vidyadhar S Melkeri1
, S L Mallikarjun2
P V Hunagund3
1,2,3
Department of PG Studies and Research in Applied Electronics Gulbarga University Kalaburgi
ABSTRACT
In this paper microstrip patch antenna is designed for 2.4GHz frequency. For the antenna
miniaturization and bandwidth improvement H-shaped DGS on microstrip patch antenna (MSA) is
used. The design of DGS has been analyzed for different dimensions of H-slot and achieved
optimized dimensions.The simulation process has been done through Finite Element Machine (FEM)
based software High Frequency Structure Simulator (HFSS) software. The properties of antenna
such as reflection co-efficient, bandwidth andgain are determined and compared with the properties
of single element square patch antenna.Further proposed antennas performance is studied for
different size of defect on the same patch antenna. Proposed antenna finds its application in wireless
LAN protocols such as Bluetooth, IEEE 802.11 and in 2.4GHz ISM Band.
Keywords: DGS, HFSS, MSA, Bandwidth, Reflection co-efficient.
1. INTRODUCTION
The microstrip patch antenna is one of the most useful antennas for low cost and compact
design for RF applications and wireless systems. In wireless mobile communication and satellite
applications, microstrip antenna has attracted much interest because of their small size, low cost on
mass production, light weight, low profile and easy integration with the other components [1-2].
Although microstrip patch antennas have many very desirable features, they generally suffer from
limited bandwidth. So the most important disadvantage of microstrip resonator antenna is their
narrow bandwidth. To overcome this problem without disturbing their principal advantage (such as
simple printed circuit structure, planar profile, light weight and cheapness), a number of methods and
structures have recently been investigated.
INTERNATIONAL JOURNAL OF ADVANCED RESEARCH IN ENGINEERING
AND TECHNOLOGY (IJARET)
ISSN 0976 - 6480 (Print)
ISSN 0976 - 6499 (Online)
Volume 6, Issue 1, January (2015), pp. 73-79
© IAEME: www.iaeme.com/ IJARET.asp
Journal Impact Factor (2015): 8.5041 (Calculated by GISI)
www.jifactor.com
IJARET
© I A E M E](https://image.slidesharecdn.com/h-shapedefectedgroundstructuredgsembeddedsquarepatchantenna-150307032417-conversion-gate01/85/H-shape-defected-ground-structure-dgs-embedded-square-patch-antenna-1-320.jpg)
![International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online), Volume 6, Issue 1, January (2015), pp. 73-79 © IAEME
74
An individual microstrip patch antenna has a typical gain of about 6 dB. Several approaches
have been used to enhance the bandwidth by perturbing the higher order mode by interpolating
surface modification into patch geometry. Gain enhancement by cutting rectangular hole on another
inserted layer. A symmetrical hole on the inserted layer is used which is the major frequency in
modern wireless communication era [3].multilayer structures [4], broad folded flat dipoles [5],
curved line and spiral antennas [6], impedance matched resonator antennas [7], resonator antennas
with capacitive coupled parasitic patch element [8], log periodic structures [9], But the most unique
technique to reduce the size of patch is to defect the ground. While comparing the antenna with the
defected ground structure and the antenna without the defected ground, the antenna having defected
ground structure reduces the size of antenna [10]. The percentage of reduction of size depends upon
the ground area that is defected. Defected Ground Structure disturbs the shielded current distribution
that depends on the dimension and shape of the defect. The current flow and the input impedance of
antenna are then influenced by the disturbance at shielded current distribution due to the DGS
structure. The DGS structure can also be used to control the excitation and the electromagnetic
waves propagating through the substrate layer [11]. A defect in the ground plane causes to increase
in effective capacitance and inductance. In this paper, microstrip antenna for low frequency at 2.4
GHz is designed and simulated using the HFSS software.
2. ANTENNA DESIGN PARAMETERS
For the designing of square microstrip patch antenna, the following equations are used to calculate
the dimensions of the square microstrip patch antenna [11].
Design consideration for required frequency.
Length L, usually 0.333 ߣ< L < 0.5 ߣ
t<<ߣ patch thickness
Height of substrate h, usually 0.003 ߣ ≤ h ≤ 0.05 ߣ
The dielectric constant is considered 2.2 ≤∈≤ 12
An effective dielectric constant ߝ must be obtained in order to account for the fringing and the
wave propagation in the line. The value of ߝis little less thanߝbecause the fringing fields around
the edge of the patch are not confined in the dielectric substrate but are also spread in the air. The
expression for ߝcan be given as:
ߝ =
ߝ + 1
2
+
ߝ − 1
2
1 + 12
ℎ
ܹ
൨
భ
మ
The dimensions of the patch along its length have now been extended on each end by a distance ∆L,
which is given empirically as:
∆ܮ = 0.412ℎ
(ߝ + 0.3) ቀ
ௐ
+ 0.264ቁ
(ߝ − 0.258) ቀ
ௐ
+ 0.8ቁ
The effective length of the patchܮnow becomes:
ܮ = ܮ + 2∆ܮ
For a given resonance frequency ݂ the effective length is given by as:
ܮ =
ܥ
2݂ඥߝ](https://image.slidesharecdn.com/h-shapedefectedgroundstructuredgsembeddedsquarepatchantenna-150307032417-conversion-gate01/85/H-shape-defected-ground-structure-dgs-embedded-square-patch-antenna-2-320.jpg)
![International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online), Volume 6, Issue 1, January (2015), pp. 73-79 © IAEME
76
The H-shaped DGS [12]has been embedded in the ground plane of the proposed antenna
which consists of the two rectangular slots and one rectangular connecting slot in the ground plane as
shown inFigure 2. Figure 3 it shows the bottom view of proposed antenna with DGS.
Figure 2: Shape of the defect in ground plain Figure 3: Bottom view of proposed DGS antenna
3. RESULTS AND DISCUSSION
The S11 parameters for the proposed antennas are calculated and simulated reflection
coefficients results are presented and compared with each otherand are shown in Figure 4.
Figure 4: Reflection co-efficient verses frequency graph.](https://image.slidesharecdn.com/h-shapedefectedgroundstructuredgsembeddedsquarepatchantenna-150307032417-conversion-gate01/85/H-shape-defected-ground-structure-dgs-embedded-square-patch-antenna-4-320.jpg)
![International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online), Volume 6, Issue 1, January (2015), pp. 73-79 © IAEME
78
Figure 9: Radiation pattern of Antenna-4
Gain is a very important parameter of every antenna. Basically, the gain is the ratio of the
radiated field intensity by test antenna to the radiated field intensity by the reference antenna [9]. In
this study, the gain of antenna is improved with DGS which is found to be 8.25dB when compared
with conventional square MSA (4.62dB).
The smith chart of antenna is shown in figure 10 andit is observed that impedance matching
is good.
Figure 10: Smith chart of antenna – 4
4. CONCLUSION
From the detailed study it is observed that the conventional antenna is designed for 2.4GHz
and further an H-shaped DGS is incorporated exactly below the patch and by doing this it is
observed that antenna is resonating at the lower frequencies. By varying the dimensions of ‘a’ and
‘b’ of DGS it is further obtained that resonating frequency is shifting to lower frequency and from
the comparative study the obtained maximum size reduction is 65.51%. By embedding DGS
bandwidth, radiation pattern and gain are also improved.These antennas find applications in wireless
LAN protocols such as Bluetooth, IEEE 802.11 and in 2.4GHz ISM Band.](https://image.slidesharecdn.com/h-shapedefectedgroundstructuredgsembeddedsquarepatchantenna-150307032417-conversion-gate01/85/H-shape-defected-ground-structure-dgs-embedded-square-patch-antenna-6-320.jpg)
H shape defected ground structure dgs- embedded square patch antenna
- 1. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online), Volume 6, Issue 1, January (2015), pp. 73-79 © IAEME 73 H-SHAPE DEFECTED GROUND STRUCTURE (DGS) EMBEDDED SQUARE PATCH ANTENNA Vidyadhar S Melkeri1 , S L Mallikarjun2 P V Hunagund3 1,2,3 Department of PG Studies and Research in Applied Electronics Gulbarga University Kalaburgi ABSTRACT In this paper microstrip patch antenna is designed for 2.4GHz frequency. For the antenna miniaturization and bandwidth improvement H-shaped DGS on microstrip patch antenna (MSA) is used. The design of DGS has been analyzed for different dimensions of H-slot and achieved optimized dimensions.The simulation process has been done through Finite Element Machine (FEM) based software High Frequency Structure Simulator (HFSS) software. The properties of antenna such as reflection co-efficient, bandwidth andgain are determined and compared with the properties of single element square patch antenna.Further proposed antennas performance is studied for different size of defect on the same patch antenna. Proposed antenna finds its application in wireless LAN protocols such as Bluetooth, IEEE 802.11 and in 2.4GHz ISM Band. Keywords: DGS, HFSS, MSA, Bandwidth, Reflection co-efficient. 1. INTRODUCTION The microstrip patch antenna is one of the most useful antennas for low cost and compact design for RF applications and wireless systems. In wireless mobile communication and satellite applications, microstrip antenna has attracted much interest because of their small size, low cost on mass production, light weight, low profile and easy integration with the other components [1-2]. Although microstrip patch antennas have many very desirable features, they generally suffer from limited bandwidth. So the most important disadvantage of microstrip resonator antenna is their narrow bandwidth. To overcome this problem without disturbing their principal advantage (such as simple printed circuit structure, planar profile, light weight and cheapness), a number of methods and structures have recently been investigated. INTERNATIONAL JOURNAL OF ADVANCED RESEARCH IN ENGINEERING AND TECHNOLOGY (IJARET) ISSN 0976 - 6480 (Print) ISSN 0976 - 6499 (Online) Volume 6, Issue 1, January (2015), pp. 73-79 © IAEME: www.iaeme.com/ IJARET.asp Journal Impact Factor (2015): 8.5041 (Calculated by GISI) www.jifactor.com IJARET © I A E M E
- 2. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online), Volume 6, Issue 1, January (2015), pp. 73-79 © IAEME 74 An individual microstrip patch antenna has a typical gain of about 6 dB. Several approaches have been used to enhance the bandwidth by perturbing the higher order mode by interpolating surface modification into patch geometry. Gain enhancement by cutting rectangular hole on another inserted layer. A symmetrical hole on the inserted layer is used which is the major frequency in modern wireless communication era [3].multilayer structures [4], broad folded flat dipoles [5], curved line and spiral antennas [6], impedance matched resonator antennas [7], resonator antennas with capacitive coupled parasitic patch element [8], log periodic structures [9], But the most unique technique to reduce the size of patch is to defect the ground. While comparing the antenna with the defected ground structure and the antenna without the defected ground, the antenna having defected ground structure reduces the size of antenna [10]. The percentage of reduction of size depends upon the ground area that is defected. Defected Ground Structure disturbs the shielded current distribution that depends on the dimension and shape of the defect. The current flow and the input impedance of antenna are then influenced by the disturbance at shielded current distribution due to the DGS structure. The DGS structure can also be used to control the excitation and the electromagnetic waves propagating through the substrate layer [11]. A defect in the ground plane causes to increase in effective capacitance and inductance. In this paper, microstrip antenna for low frequency at 2.4 GHz is designed and simulated using the HFSS software. 2. ANTENNA DESIGN PARAMETERS For the designing of square microstrip patch antenna, the following equations are used to calculate the dimensions of the square microstrip patch antenna [11]. Design consideration for required frequency. Length L, usually 0.333 ߣ< L < 0.5 ߣ t<<ߣ patch thickness Height of substrate h, usually 0.003 ߣ ≤ h ≤ 0.05 ߣ The dielectric constant is considered 2.2 ≤∈≤ 12 An effective dielectric constant ߝ must be obtained in order to account for the fringing and the wave propagation in the line. The value of ߝis little less thanߝbecause the fringing fields around the edge of the patch are not confined in the dielectric substrate but are also spread in the air. The expression for ߝcan be given as: ߝ = ߝ + 1 2 + ߝ − 1 2 1 + 12 ℎ ܹ ൨ భ మ The dimensions of the patch along its length have now been extended on each end by a distance ∆L, which is given empirically as: ∆ܮ = 0.412ℎ (ߝ + 0.3) ቀ ௐ + 0.264ቁ (ߝ − 0.258) ቀ ௐ + 0.8ቁ The effective length of the patchܮnow becomes: ܮ = ܮ + 2∆ܮ For a given resonance frequency ݂ the effective length is given by as: ܮ = ܥ 2݂ඥߝ
- 3. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online), Volume 6, Issue 1, January (2015), pp. 73-79 © IAEME 75 For a rectangular microstrip patch antenna, the resonance frequency for any ܶܯmode is givenby as: ݂ = ܥ 2ඥߝ ቀ ݉ ܮ ቁ ଶ + ቀ ݊ ܹ ቁ ଶ ൨ భ మ Where m and n are modes along L and W respectively For efficient radiation, the width W is given as: ܹ = ܥ 2݂ට (ఌೝାଵ) ଶ Substrate dimensions given as: ܮ = 6ℎ + ܹ &ܮ = 6ℎ + ܹ Where, h = substrate thickness L = length of patch ܮ = effective length W = width of patch c = speed of light ݂= resonant frequency ߝ= relative permittivity ߝ= effective permittivity ܮ = Length of ground plane ܹ = Width of ground plane Based on the above formulae a conventional square patch antenna has been designed with thickness of substrate as h=0.16cm and relative permittivityߝ = 4.2. From the analysis the length and width of patch are 3.01 cm and 3.01 cm respectively and length and width of substrate are 7.2cm and 4.2cm respectively.The proposed antenna is fed by using microstrip line feed method. Figure 1 shows the top view of conventional square MSA. Figure 1: Top view of conventional square MSA
- 4. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online), Volume 6, Issue 1, January (2015), pp. 73-79 © IAEME 76 The H-shaped DGS [12]has been embedded in the ground plane of the proposed antenna which consists of the two rectangular slots and one rectangular connecting slot in the ground plane as shown inFigure 2. Figure 3 it shows the bottom view of proposed antenna with DGS. Figure 2: Shape of the defect in ground plain Figure 3: Bottom view of proposed DGS antenna 3. RESULTS AND DISCUSSION The S11 parameters for the proposed antennas are calculated and simulated reflection coefficients results are presented and compared with each otherand are shown in Figure 4. Figure 4: Reflection co-efficient verses frequency graph.
- 5. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online), Volume 6, Issue 1, January (2015), pp. 73-79 © IAEME 77 From the above figure it is observed that antenna-1 is resonating at 1.61 GHz with impedance bandwidthof 500MHz when compared to conventional antenna, antenna-1 is showing improved impedance bandwidth of 200MHz. Further all compared results are tabulated in Table-1. Since the proposed antenna with DGS are resonating below the designed frequency. The size reduction value when compared with conventional antenna in terms of percentage is also tabulated. Table 1: Antenna parameters ANTENNAS Dimensions of DGS Resonating Frequency in GHz Reflection coefficient BW % BW in MHz Size Reduction in %A B Conventional - - 2.36 -16.50dB 1.27 300 0 Antenna-1 0.4 1.2 1.61 -26.6dB 3.12 500 49.06 Anteena-2 0.3 1.4 1.59 -24.25dB 3.11 510 50.94 Antenna-3 0.2 1.6 1.48 -23.20dB 3.36 500 62.16 Anteena-4 0.1 1.8 1.45 -16.93dB 2.73 400 65.51 The radiation patterns of the proposed antennas are shown in Figure-5 to Figure-9.From thefigures it is observed that for conventional antenna the radiation pattern is broadsided which is as shown in Figure 5 and for other antennas with DGS radiation pattern is observed to be nearly Omni directional in azimuth plain as shown in Figure-5 to Figure-9. Figure 5: Radiation pattern of conventional antenna Figure 6: Radiation pattern of Antenna-1 Figure 7: Radiation pattern of Antenna-2 Figure 8: Radiation pattern of Antenna-3
- 6. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online), Volume 6, Issue 1, January (2015), pp. 73-79 © IAEME 78 Figure 9: Radiation pattern of Antenna-4 Gain is a very important parameter of every antenna. Basically, the gain is the ratio of the radiated field intensity by test antenna to the radiated field intensity by the reference antenna [9]. In this study, the gain of antenna is improved with DGS which is found to be 8.25dB when compared with conventional square MSA (4.62dB). The smith chart of antenna is shown in figure 10 andit is observed that impedance matching is good. Figure 10: Smith chart of antenna – 4 4. CONCLUSION From the detailed study it is observed that the conventional antenna is designed for 2.4GHz and further an H-shaped DGS is incorporated exactly below the patch and by doing this it is observed that antenna is resonating at the lower frequencies. By varying the dimensions of ‘a’ and ‘b’ of DGS it is further obtained that resonating frequency is shifting to lower frequency and from the comparative study the obtained maximum size reduction is 65.51%. By embedding DGS bandwidth, radiation pattern and gain are also improved.These antennas find applications in wireless LAN protocols such as Bluetooth, IEEE 802.11 and in 2.4GHz ISM Band.
- 7. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online), Volume 6, Issue 1, January (2015), pp. 73-79 © IAEME 79 REFERENCES 1. Constantine A Balanis. 2005. Antenna Theory, Analysis and Design. John Wiley & Sons Inc, 2nd Edition (Reprint). 2. K. L. Wong. 2003. Compact and Broadband Microstrip Antennas. John Wiley & Sons. 3. Hall, P. S. Wood, C and Garrett, C, ―Wide bandwidth microstrip antennas for circuit integration, Electron. Lett. , 15, pp. 458-460, 1979. 4. Dubost, G., Nicolas, M. and Havot, H. ―Theory an applications of broadband microstrip antennasǁ, Proceedings of the 6th European Microwave Conference, Rome, pp. 21S—219, 1976. 5. Wood, C,―Curved microstrip lines as compact wideband circularly polarised antennasǁ, IEE J. Microwaves, Opt. &Acoust, 3, pp. 5-13, 1979. 6. Van De Capelle, A., De Bruyne J., Verstraete, M., Pues, H. and Vandensande J. Microstrip spiral antennasǁ, Proceedings of the International IEEE Symposium on Antennas and Propagation, Seattle, pp. 383-386, 1979. 7. Pues H. F. and Van De Capelle A. R. ―Impedance-matching of microstrip resonator antennasǁ Proceedings of the North American Radio Science Meeting, Quebec, p. 189, 1980. 8. H. Pues, Ir., J. Bogaers, Ir., R. Pieck, Ir. and A. Van de Capelle, Dr. Ir. ―Wideband quasi- log-periodic microstrip antennaǁ, IEE PROC, Vol. 128, Pt. H, No. 3, , pp. 159-163, June 1981. 9. RampalKushwaha, Prof. Kanchan Cecil, “Design and analysis of gain for rectangular microstrip patch antenna using symmetrical cuts”, International Journal of Advance Technology & Engineering Research (IJATER), November 2011. 10. L. H. Weng, Y. C. Guo, X. W. Shi, and X. Q. Chen, “An Overview On Defected Ground Structure”, Progress In Electromagnetics Research B, Vol. 7, 173–189, 2008 11. P. Bhartia, I. Bahl, R. Garg, and A. Ittipiboon, Microstrip Antenna Design Handbook, Artech House, Norwood, Mass,USA, 2000. 12. RammohanMudgal, Laxmi Shrivastava International Journal of Technology Enhancements and Emerging Engineering Research, Vol 2, Issue 2, ISSN 2347-4289. 13. Chandan Kumar Ghosh, “Reduction of Mutual Coupling Between Patch Elements Using Split-Ring DGS” International journal of Electronics and Communication Engineering &Technology (IJECET), Volume 1, Issue 1, 2010, pp. 18 - 24, ISSN Print: 0976- 6464, ISSN Online: 0976 –6472. 14. Tauheed Qamar, Naseem Halder , Mohd. Gulman Siddiqui, Vishal Varshney, “Simulation and Analysis of Slot-Coupled Patch Antenna At Different Frequencies Using HFSS” International journal of Electronics and Communication Engineering &Technology (IJECET), Volume 3, Issue 3, 2012, pp. 1 - 7, ISSN Print: 0976- 6464, ISSN Online: 0976 – 6472. 15. Arivumani Samson .S, Sankar .K and Bargavi .R, “Stacked Layer Configuration of Micro Strip Patch Antenna with Different Shapes of Patches” International journal of Electronics and Communication Engineering &Technology (IJECET), Volume 5, Issue 5, 2014, pp. 96 - 104, ISSN Print: 0976- 6464, ISSN Online: 0976 –6472.