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

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© 2012 JOT

www.journaloftelecommunications.co.uk

Design of Modified Sierpinski Gasket Fractal Antenna

Sanjeev Budhauliya1, Suneel Yadav2, and Dr. P.K. Singhal3

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

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 fre-quency independent antenna after the design of self-similar 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 sier-pinski 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 an-tenna is proposed. The modified sierpinski gasket fractal antenna shows the ability to create multiband frequen-cies. The multiband behavior of the modified sierpinski gasket fractal antenna is described in terms of number of iterations, return losses, and radiation patterns. The radi-tion 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 paricu-lar case. The iterations from zero stage to second stage are shown in Fig. 1. The design is fabricated using glass-

epoxy material with relative permittivity, r = 4.4, dielec-

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

the cooper clad.

a) Stage 0

b) Stage 1

I

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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.

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c) Stage 2 Fig. 1 The stages of iteration of modified sierpinski gasket fractal

antenna. 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 effa of the gasket fractal antenna can be

calculated by using (1) and (2).

rf

ca

3

2 ……… (1)

r

r

r

eff

a

h

a

h

a

h

a

h

a

h

aa

1802.9

182.6436.16

853.12199.21

2

2

..…... (2) Where, c = Velocity of light in free space

f = Resonant frequency

h = Height of the substrate

r = Dielectric constant of the dielectric

Thus, an equilateral tringle with side effa 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 intersec-tion of three medians of the base tringle and the radius is

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 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 fre-quency 1.0GHz and 3.5GHz respectively are obtained from simulation.

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.

Frequency

1.0GHz

3.5GHz

Return loss

-22.5dB

-48.75dB

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

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(a)

(b)

(c)

(d)

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 an-tenna. 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.

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.

Frequency

1.88GHz

3.45GHz

3.68GHz

Return loss

-22.48dB

-15dB

-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) E-

total, 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.

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

3.63GHz

3.89GHz

Return loss

-17.5dB

-14dB

-9dB

-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.

(a)

(b)

(c)

12

(d)

(e)

(f)

(g)

(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) E-

total, 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 an-tenna has been design and simulated. The multiband frequencies appeared after applied fractal technique. It was observed that as the number of iterations was in-creased, 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.

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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 An-tenna. 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 Technolo-gy, 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 De-partment 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.