Copyright © 2016 IJECCE, All right reserved 195 International Journal of Electronics Communication and Computer Engineering Volume 7, Issue 3, ISSN (Online): 2249–071X Design of Combinational Fractal Microstrip Patch Antenna using Two Feeding Techniques Dr. Yogesh Bhomia 1 , Arushi Bhardwaj 2 , Ruhika Badhan 3 Abstract – The great advances in communication system led to the demand of a multi-band, larger gain, compact, low- profile fractal antennas to hold up multiple wireless applications. The self-similarity property of Fractal antenna is advantageous in generating multiple frequencies or enhancing bandwidth. This paper describes the design and simulation of combination of sierpinski and crown shaped fractal antenna up to third iteration on IE3D software The propounded antenna is designed on 1.6mm thick FR4 substrate with dielectric constant, E r of 4.4 and is fed with 50 ohms for two types of feeding and is mounted above the ground plane at a height of 6 mm. Details of the measured and simulated results of the individual iterations is presented and discussed. Keywords – Feed, Fractal, Microstrip Antenna, Sierpenski Fasket. I. INTRODUCTION In communication system, variety of microstrip antennas are being utilized, the most usual of which is microstrip patch antenna [12]. A patch antenna is a narrow band, wide-beam, low-profile, light-weight, conformal- shaped antenna fabricated by etching the antenna element pattern in metal trace joined to an insulating dielectric substrate. It is incorporated with a flat rectangular sheet or “patch” of metal, mounted over a larger sheet of metal called a ground plane. A patch antenna is mainly constructed on a dielectric substrate employing the same materials & lithography techniques in order to make printed circuit boards. Microstrip or patch antennas [6] are becoming more and more useful because they can be printed directly onto a circuit board. Furthermore, they are becoming ubiquitous within the mobile phone market [1]. These are somewhat inexpensive to manufacture and design because of the simple 2-dimensional physical geometry. These are also proficient of dual & triple frequency operations. These are highly efficient, easily integrated to circuits, compatible to the planer & non- planer surfaces and MMIC design. All these features make microstrip antennas widely implemented in many applications, such as high performance aircrafts, wireless communication satellite and missile applications. Fractal antennas [11] can be put to use in a variety of applications, especially where space is minimal. An exemplar illustrating the advantages of fractal in antenna system is the phased arrays, where fractals can diminish mutual coupling. Additionally, microstrip patch antennas are also subjected to some drawbacks, Narrow bandwidth being a serious curb. Different techniques [2] are proposed to improve it, and one of the methods proposed by various researchers is by cutting slots on it. In this paper we have presented a design of microstrip Patch antenna using Crown & Sierpienksi fractal slots [13], with an aim to achieve a smaller size antenna [4]. Target of this work is to design a microstrip patch antenna and carrying out results using commercial simulation software like IE3D. IE3D, from zeland software, Inc.[7], is an electromagnetic simulation and optimization software useful for circuit and antenna design. IE3D has a menu driven graphic interface for model generation with automatic meshing, and uses a field solver based on full wave , method-of-moments to solve current distribution on 3D and multilayer structures of general shape. IE3D usually focuses on general planar and 3D metallic structures in layered dielectric environments. II. DESIGN OF FRACTAL ANTENNA Fig.1. Sierpenski & crown combinational with Reference, 1 st iteration, 2 nd iteration, 3 rd iteration Design Parameters The transmission line model is used to design rectangular microstrip fractal antenna. Patch Width and Length The first step is to design the patch is choosing a suitable di-electric substrate of suitable thickness. For rectangular microstrip antenna, the width W and the length L depends on the resonant frequency f r and the parameters of the substrate employed [9] To design the rectangular patch width of the antenna is given by- Width of the Patch =      (1) Where, c is the speed of light, f r is the resonant frequency. Effective Dielectric Constant ∈ reff = ( ∈ r + 1)/2 + (∈ r – 1)/ 21 + 12 ℎ/ (2) Where, ∈ reff is the effective dielectric constant, ∈ r is the dielectric constant, h is the height of the substrate, W is the width of the patch. Taking into Account the Fringing Effect The fringing fields along the width of the structure are taken as radiating slots and the patch antenna is electrically seen to be a bit larger than its physical size. ∆L = 0.412h ∈.    . ∈.!"    ." (3)