IOSR Journal of Electronics and Communication Engineering (IOSR-JECE) e-ISSN: 2278-2834,p- ISSN: 2278-8735.Volume 9, Issue 6, Ver. II (Nov - Dec. 2014), PP 01-08 www.iosrjournals.org www.iosrjournals.org 1 | Page Design and Implementation of Printed Micro strip Fractal Antennas for Wireless Applications V. Dhana Raj 1, Dr.A.M.Prasad 2, Dr.G.M.V.Prasad 3, Dr.M.Satyanarayana 4 1 Research Scholar Department of ECE, J.N.T.U College of Engineering, Kakinada 2 Professor, Department of ECE, J.N.T.U College of Engineering, Kakinada 3 Professor, Department of ECE, BVCITS, Amalapuram 4 Associate Professor Department of ECE MVGR College of Engineering Vizianagaram Abstract: The need for miniaturized antenna is ever growing in view of the advancements in wireless communication technology. The conventional micro strip antennas take any shape like square, rectangular, triangle and so on. They provide normally single resonance frequency with high quality factor because of narrow bandwidth. However, the fractal antennas are able to provide either multi-band resonances or broad bandwidth because of the self-similar and space-filling properties. In this work, design of a Hilbert curve fractal antenna, sierpinsik gasket carpet fractal antenna is considered for single and multiband applications. Design and simulation is done using HFSS 13.0 software and fabrication is done using on FR-4 clad substrate. For second iteration and third iteration of both the fractal antennas are considered. For Hilbert curve of 2 nd iteration return loss is -19dB at 3.5 GHz and for 2 nd iteration carpet fractal antenna the return loss is -22dB at 3.5 GHz and -15dB at 7.1GHz which is a dual band characteristics.By using vector network analyzer E5071C the designed antennas are tested and various plots like return loss, VSWR, smith chart and polar plot are verified.The designed antennas are used in implantable medical (IMD) applications and other wireless applications. Index Terms: microstrip, HFSS, HCFA, IMD I. Introduction As already mentioned the fractal antennas employ the fractal geometry for their design as compare to classical antennas which employ Euclidean Geometry [1] . The two basic properties of fractals provide distinguish features to these fractal designed antennas, these are discussed with appropriate application areas below: 1. Any good antenna system requires antenna scaling which means that the different parameters (impedance, gain, pattern etc.) remain same if all the dimensions and the wavelength are scaled by same factor. Since due to self-similarity possessed by fractals, the fractal structure appear to be same independent of size scaling and thus it can be interpreted that the fractal structures can be used to realize antenna designs over a large band of frequencies . The antenna can be operated similarly at various frequencies which mean that the antenna keeps the similar radiation parameters through several bands. Application: In modern wireless communications more and more systems are introduced which integrate many technologies and are often required to operate at multiple frequency bands. Thus demands antenna systems which can accommodate this integration. Examples of systems using a multi-band antenna are varieties of common wireless networking cards used in laptop computers. These can communicate on 802.11b networks at 2.4 GHz and 802.11g networks at 5 GHz. Use of fractal self-similar patterns offers solution. 2. Another requirement by the compact wireless systems for antenna design is the compact size. The fractional dimension and space filling property of fractal shapes allow the fractal shaped antennas to utilize the small surrounding space effectively. This also overcomes the limitation of performance of small classical antennas. Application: The fractal antenna technology can be applied to cellular handsets. Because fractal antennas are more compact, they fit more easily in the receiver package [4] . Currently, many cellular handsets use quarter wavelength monopoles which are essentially sections of radiating wires cut to a determined length. Although simple, they have excellent radiation properties II. Fractal Geometry Fractal geometries have two common properties: Self-similar property, Space filling property. The self- similarity property of fractals gives results in a multiband behavior of an antenna. Using the self-similarity properties a fractal antenna can be designed to receive and transmit over a wide range of frequencies because it acts as a multiband [2] . While using space filling properties, a fractal make reduce antenna size. Hilbert curve fractal geometry has a space filling property.