JOURNAL OF TELECOMMUNICATIONS, VOLUME 13, ISSUE 1, MARCH 2012 7

Design of Modified Sierpinski Gasket Fractal Antenna Sanjeev Budhauliya 1, Suneel Yadav 2, and Dr. P.K. Singhal 3 Abstract— In this paper, the design and fabrication of modified sierpinski gasket fractal antenna is studied. The analysis took place between ranges of 0.5GHz to 4GHz. In particular, multiband frequencies of the modified sierpinski gasket fractal antenna are described. There are nine resonant frequencies appear at 1GHz, 1.79GHz, 1.88GHz, 3.40GHZ, 3.45GHz, 3.5GHz, 3.63GHZ, 3.68GHz, and 3.89GHz. In addition, on the basis of return losses, number of iterations, and radition patterns, multiband behavior of the modified sierpinski gasket fractal antenna is studied. IE3D software is used to simulate the results for return losses and radition patterns. Index Terms— Fractals, Multiband frequency

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I. INTRODUCTION

I

N modern telecommunication, system require antennas with smaller dimensions and wider bandwidth than conventional one. Recently there has been developing interests in fractal geometries for antenna application with varying degrees of success in improving antenna characteristics. Basically, fractal antennas exhibit the frequency independent antenna after the design of selfsimilar shapes. Several antenna configurations based on fractal geometries have been reported in recent years [1], [2]. Fractal geometry allows designing miniature antenna and integrating multiple telecommunication services into single device. The typical sierpinski gasket antenna has been introduced by [3]. Recently various modified sierpinski gasket antenna have been developed for multiband application [4[, [5]. For sierpinski gasket antennas, the multiband behavior of the antenna is periodic in relation to the self-similar fractal gap structure of the antenna. In this paper, a modified sierpinski gasket fractal antenna is proposed. The modified sierpinski gasket fractal antenna shows the ability to create multiband frequencies. The multiband behavior of the modified sierpinski gasket fractal antenna is described in terms of number of iterations, return losses, and radiation patterns. The radition patterns of the measured modified sierpinski gasket fractal antenna clearly show the power radiated by an antenna at different frequencies. The rest of paper is organized as follows. Section II, briefly describes the antenna configuration. Section III, presents results and discussions, followed by concluding remarks in section IV.

II. ANTENNA CONFIGURATION The antenna is feed with the transmission line feeding technique. The modified sierpinski gasket antenna has been constructed through second iterations in this paricular case. The iterations from zero stage to second stage are shown in Fig. 1. The design is fabricated using glassepoxy material with relative permittivity,

tric thickness, h =1.66mm, where the radiating element is the cooper clad.

a)

Stage 0

b)

Stage 1

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 Assistant Professor, ECE Department, M.I.E.T, Meerut, India  M.Tech student, (Digital Communication), ABV-IIITM, Gwalior,India  Prof. & Head, ECEDMadhav Institute of Tech. & Science, Gwalior, India.

 r = 4.4, dielec-

© 2012 JOT www.journaloftelecommunications.co.uk

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one third of median is removed from the base tringle. Thus, the original base shape tringle is converted into hollow tringle as shown by stage 1 in Fig.1 (b). Now, for second iteration, small circles are removed from the first iteration having radius of one third of the small circle and at equal distance from the vertices of base tringle as shown by stage 2 in Fig. 1 (c).

III. RESULTS AND DISCUSSION

c)

Stage 2

Fig. 1 The stages of iteration of modified sierpinski gasket fractal antenna.

Fig. 2 shows the variation of return loss with frequency for base shape of gasket fractal antenna. It may be noted from Fig. 2, the return loss -22.5dB and -49.75dB with frequency 1.0GHz and 3.5GHz respectively are obtained from simulation.

The design of the modified gasket antenna starts with single element using an equilateral triangle conductor on a ground dielectric substrate. The operating frequency is at 1.00 GHz. Side

aeff of the gasket fractal antenna can be

calculated by using (1) and (2).

a

a eff

2c 3f r

……… (1)

  h h 1  2.199   12.853 a  a  r   2  h   h   6.182   a  16.436 a  a r   2     9.802 h   1    a    r  

           

Fig. 2 Variation of return loss with frequency for base shape of gasket fractal antenna.

Table 1 Frequencies at Which Minimum Return Loss Occur For Base Shape.

..…... (2) Where,

Frequency

1.0GHz

3.5GHz

Return loss

-22.5dB

-48.75dB

c = Velocity of light in free space

f

= Resonant frequency

h

= Height of the substrate

r

Fig. 3 shows the radiation patterns for base shape of gasket fractal antenna at frequency 1.0GHz amd 3.5GHz.

= Dielectric constant of the dielectric

Thus, an equilateral tringle with side

aeff is the base

shape of gasket fractal antenna as shown by stage 0 in Fig. 1 (a). For first iteration, a circle whose center is the intersection of three medians of the base tringle and the radius is

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(d)

(a)

Fig. 3 Radiation patterns for base shape of gasket fractal antenna (a) E-total, phi = 0(deg) at 1.0GHz (b) E-total, phi = 90(deg) at 1.0GHz (c) E-total, phi = 0(deg) at 3.5GHz (d) E-total, phi =90(deg) at 3.5GHz

Fig. 4 shows the variation of return loss with frequency for first iteration of modified sierpinski gasket fractal antenna. It may be seen from Fig. 4, the return loss -22.48dB, -15dB, and -22dB with frequency 1.88GHz, 3.45GHz, and 3.68GHz respectively are obtained from simulation.

(b)

Fig. 4 Variation of return loss with frequency for first iteration of modified sierpinski gasket fractal antenna.

Table 2 Frequencies at Which Minimum Return Loss Occur For First Iteration.

(c)

Frequency

1.88GHz

3.45GHz

Return loss

-22.48dB

-15dB

3.68GHz -22dB

Fig.5 shows the radiation patterns for the first iteration of modified sierpinski gasket fractal antenna at frequency 1.88GHz, 3.45GHz, and 3.68GHz.

10

(a)

(b)

(c)

(d)

(e)

(f)

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Fig. 5 Radiation patterns for first iteration of modified sierpinski gasket fractal antenna (a) E-total, phi = 0(deg) at 1.88GHz (b) E-total, phi = 90(deg) at 1.88GHz (c) E-total, phi = 0(deg) at 3.45GHz (d) Etotal, phi =90(deg) at 3.45GHz (e) E-total, phi = 0(deg) at 3.68GHz (f) E-total, phi = 90(deg) at 3.68GHz

Fig. 6 shows the variation of return loss with frequency for second iteration of modified sierpinski gasket fractal antenna. It may be noted from Fig. 6, the return loss 17.5dB, -14.0dB, -9.0dB, and -19.0dB with frequency 1.79GHz, 3.40GHz, 3.63GHz, and 3.89GHz respectively are obtained from simulation.

(a)

Fig. 6 Variation of return loss with frequency for second iteration of modified sierpinski gasket fractal antenna.

Table 3 Frequencies at Which Minimum Return Loss Occur For Second Iteration.

Frequency

1.79GHz

3.40GHz

Return loss

-17.5dB

-14dB

3.63GHz

-9dB

(b)

3.89GHz

-19dB

Fig.7 shows the radiation patterns for the second iteration of modified sierpinski gasket fractal antenna at frequency 1.79GHz, 3.40GHz, 3.63GHz, and 3.89GHz.

(c)

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(g)

(d)

(e)

(h) Fig. 7 Radiation patterns for second iteration of modified sierpinski gasket fractal antenna (a) E-total, phi = 0(deg) at 1.79GHz (b) E-total, phi = 90(deg) at 1.79GHz (c) E-total, phi = 0(deg) at 3.40GHz (d) Etotal, phi =90(deg) at 3.40GHz (e) E-total, phi = 0(deg) at 3.63GHz (f) E-total, phi = 90(deg) at 3.63GHz (g) E-total, phi = 0(deg) at 3.89GHz (h) E-total, phi = 90(deg) at 3.89GHz

IV. CONCLUSION

In this work, a modified sierpinski gasket fractal antenna has been design and simulated. The multiband frequencies appeared after applied fractal technique. It was observed that as the number of iterations was increased, number of frequency band also increased. For zero iteration two bands occur, for first iteration three bands occur, and for second iteration four bands occur. This modified sierpinski gasket fractal antenna can be used for GPS, WLAN, WI-MAX, Cognitive Radio, and UWB. (f)

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[2]

[3]

[4]

[5]

[6] [7]

J. Gianvittorio and Y. Rahmat samii, “ Fractal Patch Antenna”, Department of Electrical Engineering, University of California, Los Angeles, 2006. KJ Vinoy, “Fractal Shaped Antenna Element for Wide and Multiband Wireless Application”, Pennsylvania State university, Ph.d Thesis, 2002. Puente-Baliarda, C., Romeu, J., Pous, R., and Cardama, A., “On the Behaveior of the Sierpinski Multiband Fractal Antenna”, IEEE Transaction on Antenna Propagation, vol. 46, no. 4, pp. 517525, 1998. Song, C.T.P., Hall, P.S., and Ghafouri-Shiraz, H., “ Shorted Fractal Sierpinski Monopole Antenna”, IEEE Transaction on Antenna Propagation, vol. 52, no. 10, pp. 2564-2570, 2004. Liu, J.C., Wu, C.Y., Chen, D.C., and Chen, J.Y., “ Modified Sierpinski Fractal Monopole Antenna with Descartes Circle Theoram”, Microwave Opt. Technol. Lett., vol. 48, no. 5, pp. 909-911, 2006. Constantine A. Balanis, “Antenna Theory”, Second Edition, John Wiley & Sons, 2007. David M. Pozar, “Microstrip Antenna”, IEEE Transaction on Antenna and Propagation, 1992.

Mr. Sanjeev Budhauliya received B.Tech degree in Electronics and Communication from U.P.T.U in 2004. In 2011, he received M.Tech degree in digital Communication from U.P.T.U. & presently working as an Assistant Professor in Meerut Institute of Engineering and Technology, Meerut affiliated by U.P.T.U. Lucknow, India. His areas of research intrests include Fractal Antenna Designing, Patch Antenna. He written one book on Network Analysis and Synthesis with ISBN 93-8080-304-4 published by KNRN, Meerut, in 2010. Mr. Suneel Yadav received B.Tech degree in Electronics and Communication from Meerut Institute of Engineering and Technology, Meerut in 2008. Currently, he is pursuing M.Tech in Digital Communication from ABV- Indian Institute of Information Technology and Management, Gwalior, India. His current research intrests are Cognitive Radio, Cooperative Communication, Image Processing in PACS, Designing of fractal antennas. Prof. P.K.Singhal presently working as a Professor & Head in Department of Electronics in Madhav institute of Technology & Science, Gwalior, and published more than hundred research papers, which include papers in IEEE transaction, international & National Journals, International & National Conferences.