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IJAIEM-2013-04-29-103

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					       Web Site: www.ijaiem.org Email: editor@ijaiem.org, editorijaiem@gmail.com
Volume 2, Issue 4, April 2013                                           ISSN 2319 - 4847



                Bandwidth Enhancement in Multipatch
                     Microstrip Antenna Array
                 Shubham Gupta1, Mukul Singh2, Rahul Yadav2 , Sanee Kr. Patel2 , Shivam Singh2
     1
         Assistant Professor, Department of Electronics & Communication, GLNA Institute of Technology, Mathura,
                                                           India
          2
            Students, Department of Electronics & Communication, GLNA Institute of Technology, Mathura, India



                                                       ABSTRACT
In this paper a microstrip patch antenna has been used for microwave frequency. The patch antenna is printed on RT/DUROID
5880. In addition a rectangular conducting plate of comparable dimensions was placed above the patch in order to enhance the
bandwidth. The package was used to analyze the effect of the top patch, in particular the variation of VSWR with two
parameters, namely the distance between the two patches and the size of the upper patch. Simulation and experiment result of a
constructed array of two multipatch microstrip antenna with resonance frequency at 5.2 GHz shows the return loss S11 of
about -29 dB, gain level of about 10.683 dB with 23.07% bandwidth improvement and after that we have designed an array of
three multipatch microstrip antenna and achieved a bandwidth about 29.61% with directivity about 11.47 dB and return loss -
29 dB at the frequency 5.74GHz.
Keywords: Multipatch Microstrip Antenna, Microstrip antennas (MSA), Resonant frequency, Advanced Design
System(ADS).

1. INTRODUCTION
Microstrip antennas are used in a wide range of applications, but due to its narrow impedance bandwidth restriction
occurs. Microstrip patch antenna is very well known form of printed antenna. Microstrip patch antennas are getting
popular in wireless application due to their low profile structure, simple geometry and low fabrication cost. It is a very
important element in communications and radar applications since it provides a wide variety of designs, either planar
or conformal. Microstrip antennas can be fed by various techniques, besides its advantage of being compact and
suitable for antenna array designs. The microstrip antenna generally consists of a radiating element (patch), an
intermediate dielectric layer, and a ground plane. The radiating element or patch is generally made of conducting
material such as copper or gold and can take any possible shape like rectangular, square, circular, elliptical, triangular
etc.
Microstrip antenna performance is affected by the patch geometry, substrate properties and feed techniques. One of the
advantages of microstrip antennas is the freedom to choose from a variety of patch geometries. A dielectric substrate
with properties such as low loss, low dielectric, and sufficiently thick substrate can provide maximum radiation
efficiency and bandwidth. However, the antenna dimensions are large when low dielectric substrates are used. Low loss
substrates provide good radiation efficiency, but also make the microstrip antenna a high-Q device, resulting in narrow
bandwidth. The use of high dielectric substrates with higher loss gives reduced performance, but greater bandwidth and
smaller dimensions.
2. Multipatch Microstrip Antenna
When an antenna has more than one patch over the dielectric substrate it is called as a Multipatch Microstrip antenna.
Multipatch Microstrip antenna provides basic information on patch antenna design and operation, directed to engineers
who are mainly designers of RF/microwave circuits. In high performance aircraft, spacecraft, satellite and missile
applications, where size, weight, cost, performance, ease of installation and aerodynamic profiles are important, low
profile antennas may be required. To meet these requirements, Multipatch Microstrip antennas are used. Multipatch
antennas are narrowband, wide beam antennas fabricated by etching the antenna element pattern in metal trace bonded
to an insulating dielectric substrate with a continuous multi metal layer bonded to the opposite side of the substrate
which forms a ground plane.




                                              Figure.1. Multipatch Microstrip Antenna

Volume 2, Issue 4, April 2013                                                                                     Page 353
       Web Site: www.ijaiem.org Email: editor@ijaiem.org, editorijaiem@gmail.com
Volume 2, Issue 4, April 2013                                           ISSN 2319 - 4847

The relation for the resonant frequency of the multidielectric layer Microstrip Antenna can be expressed as




The relation for the quasi static permittivity of the multidielectric layer can be expressed as




Where q1, q2 and q3 are filling factors respectively. The length of the patch can be obtained by determining the effect
of frequency on the substrate permittivity. The dispersive behavior of the permittivity can be determined as




Where e is the permittivity which takes into account          r   and   eff   multilayer effect on a microstrip line as all the
formulae calculated were for single layer.




Where the parameter A can be expressed by eq. given below in terms of h12, the height between layers 1 and 2 and W.




3. Design of Multipatch Microstrip Antenna
Antennas with dual patch consist of a very thin metallic strip (lower patch) placed a small fraction of a wavelength
above a ground plane. Another thin rectangular parasitic conducting plate (21.6 x 16.4 mm) is placed above lower
patch is separated by an air gap ( r = 1.07) of width 2.2mm. A microstrip feed is also connected to the patch. The
Multipatch is designed so its pattern is maximum normal to the patch.




                                         Figure. 2. Layout of Single Patch on ADS momentum with feed line
The figure shows 21.6 x 16.4 mm rectangular patch connects with a feed line. A multilayer antenna substrate of low
electrical loss, and the upper honeycomb, prevent surface wave propagation and increase the bandwidth. The antenna
patch is deposited on the underside of the substrate which acts as a protective cover.

4. Multipatch Microstrip antenna Array
Microstrip antennas are very versatile and are used, among other things, to synthesize a required pattern that cannot
always be achieved with a single element. A standard configuration for microstrip antenna is a single rectangular
patch. It consists of sandwich of two parallel conducting layer separated by single thin dielectric substrate. The lower
conductor function as ground plane and upper conductor represents the antenna radiating part. This is simple
configuration that is rugged and relatively easy to fabricate, but it is limited in its bandwidth. The bandwidth is limited
to 0.5%-2%. Nowadays several methods have been attempted to enhance the bandwidth. One effective method is to add
a second patch in front of the basic one, resulting in the so called dual patch microstrip

Volume 2, Issue 4, April 2013                                                                                       Page 354
       Web Site: www.ijaiem.org Email: editor@ijaiem.org, editorijaiem@gmail.com
Volume 2, Issue 4, April 2013                                           ISSN 2319 - 4847

Antenna .The concept of stacking patches is realized through electromagnetic coupling which gives the bandwidth
enhancement. Microstrip antenna arrays became very popular for their low profile and lightweight as well as their
flexibility. The major advantage of Microstrip array antenna is the increased gain and directivity. The elements can be
fed by a single line or by multiple lines in a feed network arrangement. In addition, they are used to scan beam of an
antenna system, increase the directivity and gain, and perform various other functions which would be difficult with a
single element.
Microstrip Arrays are limited in that they tend to radiate efficiently only over a narrow band of frequencies and they
cannot operate at the high power levels of waveguide, coaxial line or strip line. With the need for light weight missile
antennas and strip line transmission surface they have assumed an increasingly large share of the conformal missile
antenna developments. The introduction of microstrip elements conformal to space vehicles and the obvious potential
of such light weight array antennas lead to substantial interest in extending this technology towards full scanning
capability.
5. Simulation and analysis of an array of two multipatch microstrip antenna




Figure.3. Layout scheme of transformed rectangular patch on ADS momentum with Multipath Array and feeding line




                                                 Figure.4. 3D view of Multipatch array




                              Figure.5. Return losses at the resonant frequency 5.2 GHz




                                            Figure.6. Antenna parameters from Momentum (ADS)


Volume 2, Issue 4, April 2013                                                                               Page 355
       Web Site: www.ijaiem.org Email: editor@ijaiem.org, editorijaiem@gmail.com
Volume 2, Issue 4, April 2013                                           ISSN 2319 - 4847


A Multipatch microstrip antenna array has been successfully designed by calculating all the parameters required for it
on a particular frequency requirement. Its simulation is done on ADS, with optimized parameters.

                                        Frequency             5.2GHz
                                        Return loss           -29 dB
                                        Gain                  10.0683dB
                                        Directivity           10.7524 dB
                                        Efficiency            99.35 %
                                        Bandwidth             23.07%

                                              Table.1. The results obtained

6. Simulation and analysis of an array of three multipatch microstrip antenna
Here an Array of three Multipatch Microstrip Antenna has been designed. Here we are more concerned to enhance the
directivity of an antenna so we have attached one more antenna to the array of two multipatch microstrip antennas to
improve the bandwidth and directivity. Its simulation is done on ADS, with optimized parameters.




                                  Figure.7. Layout of triple Patch on ADS momentum with feed line




                                             Figure.8. 3D view of Multipatch array




                                         Figure.9. Return losses at the resonant frequency 5.74 GHz



Volume 2, Issue 4, April 2013                                                                             Page 356
       Web Site: www.ijaiem.org Email: editor@ijaiem.org, editorijaiem@gmail.com
Volume 2, Issue 4, April 2013                                           ISSN 2319 - 4847




                                   Figure.10. Antenna parameters from Momentum (ADS)

                                          Frequency           5.74 GHz
                                          Return loss         -29 dB
                                          Gain                8.72897dB
                                          Directivity         11.4703 dB
                                          Efficiency          76.10 %
                                          Bandwidth           29.61%

                                             Table.2. The results obtained


7. CONCLUSION
This paper has been presented for the purpose that to increase the bandwidth and directivity we should use the
multilayer multipatch microstrip antenna. Using this technique we have also improved the directivity of antenna which
is highly desirable for high performance fighter aircraft. For achieving the highly directional antenna we have designed
an array of multipatch microstrip antenna and achieved a bandwidth of 29.61% and directivity of 11.4703dB.

REFERENCES
[1]Constantine A. Balanis, Antenna Theory Analysis and Design, John Willy & Sons, 2ndEd. 1997, Chap.14.
[2] R.Garg, P.Bhartia, I.Bahl, and A.Ittipiboon, Microstrip Antenna Design Handbook, Artech House.
[3]Girish Kumar, K. P. Ray, Broadband Microstrip Antennas, Artech House, 2nd Edition, Boston, London.
[3] Lars Josefsson and Patrick Persson, Conformal Array Antenna Theory and Design, IEEE Press Series, 2006.
[4] Rushit D Trivedi, Vedvyas Dwivedi. “Stacked Microstrip Patch Antenna: Gain and bandwidth improvement, Effect
     of patch Antenna,2012 International Conference on Communication System and Network Technologies © 2012
     IEEE DOI 10.1109/CSNT.2012.19 .
[5]D.Yoharaaj, Raja Syamsul Azmir, Alyani Ismail, “A New Approach for Bandwidth Enhancement Technique in
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     September 12 - 14, 2006, Putrajaya, Malaysia.
[6].Gary Breed, Editorial Director, “The Fundamentals of Patch Antenna Design and Performance”, From March 2009
     High Frequency Electronics, Copyright © 2009 Summit Technical Media, LLC.
[7] David M. Pozar “A Review of Aperture Coupled Microstrip antennas-History, Operation, Development, and
     Applications” Electrical and Computer Engineering, University of Massachusetts at Amherst, Amherst, MA
     01003, May 1996.
[8] Dongseob Kim, Chisang You, Woonbong Hwang, “Effect of adhesive bonds on electrical performance in multi-
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[9] G. Yang*, M. Ali, SeniorMember, IEEE, and R. Dougal, SeniorMember, IEEE “A Multi-Functional Stacked Patch
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[10] Gary Breed Editorial Director “The Fundamentals of Patch Antenna Design and Performance” pp 48-51 March
     2009.
Volume 2, Issue 4, April 2013                                                                               Page 357
       Web Site: www.ijaiem.org Email: editor@ijaiem.org, editorijaiem@gmail.com
Volume 2, Issue 4, April 2013                                           ISSN 2319 - 4847

[11] Prabhakar Singh, Nagendra Prasad Yadav and J. A. Ansari “A Multilayer Rectangular Patch Antenna For
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[12] BAZEYI HATEGEKIMANA JEYASINGH NITHIANANDAM “A Wideband Multilayer Microstrip Patch
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[13] J. A. Ansari · N. P. Yadav · Anurag Mishra · Prabhakar Singh Babau R. Vishvakarma “Analysis of Multilayer
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[14] M. Pozar,”A reciprocity method of analysis for printed slot and slot coupledmicrostrip antennas”, IEEE Trans.
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[15] Bahl I, Bhartia P, Stuchly S. Design of microstrip antennas covered with a dielectric layer, IEEE Trans Antennas
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[16] Hall, P.S., & James, J.R. :‘Handbook of Microstrip Antennas’, IEEE Electromagnetic Wave Series, 1989.
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AUTHOR’S BIOGRAPHY

              Shubham Gupta is an Assistant Professor in Electronics and Communication Engineering Department
              in GLNA Institute of Technology, Mathura. He has completed M.Tech from Jaypee Institute of
              Information Technology in the year of 2011 in the field of Electronics and Communication Engineering.
              Prior to that he has done been B.Tech from Jaypee University of Information Technology, Shimla in the
              year of 2009 in the field of Electronics and Communication Engineering, He has interest on Microstrip
                 Patch Antenna, mobile and Wireless Communication


               Rahul Yadav is a final year student of GLNA Institute of Technology, Mathura in the Department of
               Electronics and Communication Engineering. Now he has been working on an Array of Microstrip
               patch antenna design in final year of B.Tech from Gautam Buddh Technical University (GBTU),
               Lucknow, India.


                Shivam Singh is a final year student of GLNA Institute of Technology, Mathura in the Department of
                Electronics and Communication Engineering. He has been working on an Array of Microstrip patch
                antenna design in final year of B.Tech from Gautam Buddh Technical University (GBTU), Lucknow,
                India.


                Mukul Singh is a final year student of GLNA Institute of Technology, Mathura in the Department of
                Electronics and Communication Engineering. He has been working on an Array of Microstrip patch
                antenna design in final year of B.Tech from Gautam Buddh Technical University (GBTU), Lucknow,
                India.


               Sanee Kr. Patel is a final year student of GLNA Institute of Technology, Mathura in the Department
               of Electronics and Communication Engineering. He has been working on an Array of Microstrip patch
               antenna design in final year of B.Tech from Gautam Buddh Technical University (GBTU), Lucknow,
               India.




Volume 2, Issue 4, April 2013                                                                            Page 358

				
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