This document summarizes a project on designing a dual band microstrip antenna. It provides an overview of microstrip antennas, including their basic principles and operation, common shapes and feeding techniques. It then describes the design of a circular dual band microstrip antenna with a T-shaped slot to achieve resonance at 2.3 GHz and 5.8 GHz. Simulation results showing return loss, VSWR, and radiation patterns are presented. Potential applications of dual band microstrip antennas in mobile satellite communication systems, wireless LANs, and GPS are also discussed.

1. A
Project on
“ DUAL BAND MICROSTRIP ANTENNA”
PRESENTED BY
Mr. Kadri Anas (20100354)
UNDER GUIDANCE OF
Mr. S. V. Khobragade
DEPARTMENT OF ELECTRONICS & TELECOMMUNICATION ENGINEERING
DR. BABASAHEB AMBEDKAR TECHNOLOGICAL UNIVERSITY
LONERE-RAIGAD
2013-2014

2. Overview.
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Antenna
Microstrip Patch Antenna
Feeding Techniques
Advantages/Disadvantages
Dual Band Microstrip Antenna
Future Work
References

3. Antenna.
• A metallic device for radiating or receiving radio waves.
• A transitional structure between free space & a guiding device.
Types Of Antennas
a) Wire Antennas
b) Aperture Antennas
c) Microstrip Antennas
d) Reflector Antennas
e) Lens Antennas

4. Microstrip Antenna.
Dielectric substrate
Antenna Patch
Ground plane
o In its most basic form, a Microstrip patch antenna consists of a radiating patch on
one side of a dielectric substrate which has a ground plane on the other side.

5. Basic Principles of Operation.
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The patch acts approximately as a resonant cavity (short circuit walls on
top and bottom, open-circuit walls on the sides).
If the antenna is excited at a resonant frequency, a strong field is set up
inside the cavity, and a strong current on the surface of the patch. This
produces significant radiation.

6. 
The radiating patch can be of any shape such as circular,
rectangular, triangular, sectoral , annular ring, semicircular .
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Low profile, conformable to various surfaces, inexpensive, durable,
but narrow-band.
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For good antenna performance, a thick dielectric substrate having a
low dielectric constant is desirable since this provides better
efficiency, larger bandwidth and better radiation .
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Micro strip patch antenna or patch antenna is a narrow band ,widebeam antenna.
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A thicker substrate will increase the radiation power , reduce
conductor loss and improve Band width.

7. Shapes of Microstrip Patch.

8. Feeding Techniques.
1.Microstrip Line Feed.
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A conducting strip is connected to the edge of
the patch. The feed can be etched on the
substrate.
2.Capacitive Feeding.
• In this type of feeding the feeding is
done to small aonther patch instead of
main radiating patch.

9. 3. Coaxial Feeding.
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The Coaxial feed or probe feed is a very common technique used for
feeding Microstrip patch antennas.
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The center conductor of the coaxial connecter is soldered to the patch.
Advantages:
1.Easy to fabricate and match.
2.Low spurious radiation.
 Disadvantages:
Narrow bandwidth
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10. Effects of Key Design Parameters
on Antenna Performance
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Air Gap
Separation Distance
Dimensions of Feed Strip
Probe Diameter
Size and properties of Dielectric substrate
Different Shapes of Radiator Patch

11. Advantages
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Low weight and small volume.
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Low fabrication cost
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Allows linear and circular polarization.
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Mechanically robust.
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Capable of dual and triple frequency operations.

12. Disadvantages
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Narrow bandwidth
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Lower gain
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Low power handling capacity.
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Spurious feed radiation.
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Low efficiency

13. Remedies
 Low power and low gain can overcome by arrays configuration.
 Surface wave associated limitations such as poor efficiency,
increased mutual coupling , reduced gain and radiation pattern can
overcome.
 The band width can increase up to 60% by using Bandwidth
Enhancement Techniques.

14. Dual Band Microstrip Antenna.
 In order to design a circular microstrip antenna for multiband
applications suitable dielectric substrate of relative permittivity
Єr=4.2 and thickness h=1.6mm is chosen.
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The circular microstrip antenna has radius=16.625mm.
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T-shaped slot with appropriate dimension is provided on the circular
patch to get dual band frequencies.
• The proposed antenna is probe fed and
antenna parameters like Return Loss,
VSWR and Radiation pattern at
corresponding resonance frequencies are
simulated on HFSS.

15. Return Loss.
• The simulation of the proposed antenna is done on HFSS software,
Simulation gives dual frequencies at 2.30 GHz and 5.8 GHz.
12

16. VSWR.
• VSWR stands for Voltage Standing Wave Ratio.

17. Radiation Pattern.

18. Applications.
 Used in Mobile Satellite Communication System.(2.3 GHz)
 Wire less LAN’S.(2.3 GHz)
 GPS system.(2.3 GHz)
 Can also be used for Radio Applications.(5.8 GHz)

19. References
[1]
G. Kumar and K. P. Ray, Broadband Microstrip Antennas, Artech House,
Norwood, Mass, USA, 2003
[2] C. A. Balanis, Antenna Theory, John Wiley & Sons, Hoboken, NJ, USA,
2nd edition, 2004.
[3]
R. Garg, P. Bhartia, I. Bahl, and A. Ittipiboon,Microstrip Antenna Design
Handbook, Artech House, Norwood, Mass, USA, 2001.
[4]
A Novel Dual Band Circular Microstrip Antenna , International Journal of
Computer Applications.
[5]