Metamaterial Based Fractal Body Worn Antenna –A Review

International Journal of Advance Foundation and Research in Computer (IJAFRC)

Volume 2, Issue 8, August - 2015. ISSN 2348 – 4853, Impact Factor – 1.317

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Metamaterial Based Fractal Body Worn Antenna –A Review Swagata B Sarkar

Assistant Professor, Sri Sairam Engineering College, Chennai

[email protected]

ABSTRACT

Metamaterial are only special kind of structures through which a defect can be created either in

ground, substrate or other places of antennas. All metamaterial based antennas are known as left

handed material antenna where permittivity and permeability are negative. With the use of meta

material antenna size can be minimized as well as the radiation direction can be inverted. Meta

material antennas are very much useful for its left handed structure for which it can be used as

Body Worn Antenna, because the radiation instead of absorb by the body will be directed

outwards which can reduce the Specific absorption Rate(SAR).Normally human body parameters

dealing with low frequency signals. At low frequency, antenna size will be high. So, fractal antenna

can be designed to increase the antenna size at low frequency with minimum area. So the

proposed body worn antenna at low frequency can be designed by metamaterial fractal antenna

structure. Key Words: Metamaterial, Fractal Antenna, Body Worn Antenna

I. INTRODUCTION In recent days people are concentrating more about metamaterial based antenna design as it has lot of

advantages. In this paper hybrid approach is proposed to improve the performance of antenna for Body

Worn applications. In this paper hybridization is tried as a combination of Fractal Antenna Design,

Metamaterial design and Body worn application.

In Body Worn Antenna low frequency signal handling is required, which is easily achieved by Fractal

Antenna design [6]. The performance of SAR reduction and miniaturization can be done by the

introduction of metamaterial [4] [5]. Finally the substrate property of Body based antenna can be achieved

by the design of Body Worn Antenna.

The three techniques together is combined in this paper to get good result.

II. FRACTAL ANTENNA

The fractal geometry with electromagnetic theory has led to a new and innovative antenna designs.

Fractal antenna engineering research has been primarily focused in two areas: the first deal with the

analysis and design of fractal antenna elements, and the second concerns the application of fractal

concepts to the design of antenna arrays. Fractals have no characteristic size, and are generally composed

of many copies of themselves at different scales. These unique properties of fractals have been exploited

in order to develop a new class of antenna-element designs that are multi-band and/or compact in size.

On the other hand, fractal arrays are a subset of thinned arrays, and have been shown to possess several

highly desirable properties, including multi-band performance, low side lobe levels, and the ability to

develop rapid beam forming algorithms based on the recursive nature of fractals. Fractal elements and

arrays are also ideal candidates for use in reconfigurable systems.

There here has been an ever-growing demand, in both the military as well as the commercial sectors, for

antenna designs that possess the following highly desirable attributes:

1. Compact size




2. Low profile

3. Conformal

4. Multi-hand or broadband

Some Useful Geometry for Fractal Antenna Engineering

This section will present a brief overview of some of the more common fractal geometries that have been

found to be useful in developing new and innovative designs for antennas. The first fractals that will he

considered is the popular Sierpinski gasket.

Figure 1. Several stages in the construction of a Sierpinski gasket fractal.

Another popular fractal is known as the Koch snowflake. This fractal also starts out as a solid equilateral

triangle in the plane.

Figure 2. the first few stages of construction of Koch, snowflake

The space-filling properties of the Hilbert curve and related curves make them attractive candidates for

use in the design of fractal antennas. The first four steps in the construction of the Hilbert curve are

shown in Figure4 [2]. The Hilbert curve is an example of a space-filling fractal curve that is self-avoiding

(i.e., has no intersection points).

Figure 3. The first few stages in the construction of a Hilbert curve III. METAMATERIAL ANTENNA




Metamaterial technology is a method of reducing a microstrip patch antenna size using Defected Ground

Structure (DGS). The DGS exhibits negative permittivity and permeability proved by applying the

Nicolson- Ross-Weir (NRW) method. The performances of the antenna will improve in term of gain,

return loss, bandwidth, and Voltage Standing Wave Ratio (VSWR) by using metamaterial

Figure 4.Microstrip patch Antenna with Circular Ring DGS A metamaterial based new microstrip patch antenna design is presented for multiband applications.

Metamaterial provide unique features of obtaining high directional gain and miniaturization. Herein,

square, hexagonal and star shaped patches have been designed over a Complementary Strip Ring

Resonator loaded reactive impedance surface (CSR-RIS).

Figure 5.Top view of CSRR loaded RIS patches antenna. a) Square. b) Hexagonal. c) Star. d) Side

view of three structures. Microstrip patch antenna filled with split ring resonator array with a S-Shape patch [3].

Figure 6. Metamaterial Micro strip patch antenna design (a) top view (b) front view.

Figure 7. SRR unit cell (i) structure (ii) equivalent electric circuit




A planar Meta material antenna using offset fed diamond shaped split rings (DSSR) [1].

Figure 8. Geometrical structure of DSSR with normal cuts

A narrow band microstrip patch antenna with “Pentagonal Rings” shaped metamaterial cover is

proposed and analyzed at a height of 3.2mm from the ground plane [2].

Figure 9. Microstrip inset feed patch antenna and metamaterial structure with pentagonal ring IV. BODY WORN ANTENNA Support of ever increasing applications for wireless data and communications on a body-centric platform

requires novel antenna systems that can be integrated with the body-worn environment, while

maintaining free-range of movement and minimal mass impact. E-textile antennas show great promise

due to their ease of integration with other textile materials, and they are inherently low-mass and flexible

relative to conventional antenna materials. For body-centric applications [7], the low-mass, flexibility,

and integration simplicity of e-textile antennas can enable multiple-antenna systems, which otherwise

would be precluded by the rigidity and mass of conventional antenna materials.

V. PROPOSED ANTENNA

Based on the above review, we are going to propose a fractal body worn antenna with Meta material

substrate for biomedical application. Requirement for Hybrid antenna design:

1. Metamaterial will provide miniaturization of the antenna with desired frequency along with SAR

reduction [4] [5].

2. Body worn antenna will provide the desired flexibility [7].

3. Fractal antenna will give optimum antenna design with low frequency. Since Biomedical signals are

dealing with low frequency, so fractal array antenna will give good result [6]




Figure 10. Proposed antenna structure with ground plane [2] [6]

Table 1. Comparison of all antenna types

Fractal

Antenna

Metamaterial Antenna Body Worn

Antenna

Proposed Antenna

Advantages

Fractal

antenna can

give best

solution for

low

frequency

signal

antenna

design with

reduced

structure due

to its layout

Metamaterial have the

advantages

1.Improvement of gain

2. improvement of efficiency

3.Improvement of

bandwidth

4.Reduced return loss

5.Reduced Specific

Absorption Rate

Body worn

antenna can

give flexibility

Our proposed antenna can

give best solution for

biomedical application with

lower frequency, reduced

structure, flexibility, higher

gain, higher efficiency,

higher bandwidth, reduced

return loss and specific

absorption rate.

In proposed antenna model we are going to combine Koch, snowflake construction antenna array with

Pentagonal Rings Shaped Metamaterial ground. The full structure can be printed on flexible substrate to

meet the target of Bio Medical application .

VI. CONCLUSION

After reviewing all the paper, it is obvious that body worn with low SAR antenna can be best designed by

fractal model with metamaterial ground or substrate. So based on antenna parameter improvement like

VSWR, gain, Return loss etc, metamaterial position can be changed. SAR level also can be changed by

changing the position of antenna in the body.

VII. REFERENCES [1] Offset Fed Diamond Shaped Split Ring (DSSR) Planar Metamaterial Antenna J.G.Joshi, S.S.Pattnaik,

S. Devi, M.R. Lohokare and Chintakindi Vidyasagar Department of ETV and ECE National Institute

of Technical Teachers’ Training and Research, Chandigarh-160019, INDIA

[2] Rectangular Microstrip Patch Antenna with “Pentagonal Rings” Shaped Metamaterial Cover Bimal

Garg, Nitin Agrawal, Vijay Sharma, Ankita Tomar, Prashant Dubey Department of Electronics

Engineering, Madhav Institute of Technology and Science, Gwalior-474005, India 2012

International Conference on Communication Systems and Network Technologies

[3] S-Shape Meandered Microstrip Patch AntennaDesign using MetamaterialShobhit K. Patel

Charotar University of Science & TechnologyChanga-388421, Gujarat, India. Y.P.Kosta Marwadi

Education Foundation’s Group of Institutions Rajkot-360001, Gujarat, India




[4] Miniaturization of Microstrip Patch Antenna Through Metamaterial Approach N. Ripin, W. M. A.

W. Saidy, A. A. Sulaiman, N. E. A. Rashid, M. F. Hussin 2013 IEEE Student Conference on Research

and Development (SCOReD), 16 -17 December 2013, Putrajaya, Malaysia

[5] Multiband Microstrip Patch Antenna Design Using Metamaterial for Airborne SAR system Galaba

Sai Rajesh, Venkata Kishore K, Vijay Kumar VIT University, Vellore, Tamil nadu.

[6] An Overview' of Fractal Antenna Engineering Research Douglas H. Werner' and Suman Ganguly

'Communications and Space Sciences Laboratory, Department of Electrical Engineering The

Pennsylvania State University, University Park, PA 16802 USA 'Center For Remote Sensing, Inc.

11350 Random Hills Rd., Suite 710, Fairfax, VA 22030 USA ieee transactions on antennas and

propagation, vol. 57, no. 4, april 2009

[7] Body-Worn E-Textile Antennas: The Good, the Low-Mass, and the Conformal Timothy F. Kennedy,

Member, IEEE, Patrick W. Fink, Member, IEEE, Andrew W. Chu, Member, IEEE, Nathan J.

Champagne, II, Senior Member, IEEE, Gregory Y. Lin, and Michael A. Khayat, Member, IEEE

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Metamaterial Based Fractal Body Worn Antenna –A Review