DESIGN AND ANALYSIS OF KOCH FRACTAL ANTENNA FOR WLAN APPLICATIONS

In this paper, a Koch fractal antenna is designed for Wireless Local Area Network (WLAN) applications. Koch snowflake design is symmetrical and self-similar structure that induces space filling capability and improves the surface current on the antenna. The overall fractal antenna structure consist of a copper foils (Patch and Ground Plane) mounted on either sides of the dielectric material (Flame Retardant-4 (FR-4) with permittivity ?r =4.4 and loss tangent d=0.02). The antenna is fed using a microstrip line feed. The dimensions of the Koch fractal antenna are 30?30?1.6mm3 which is compact sized design made on High Frequency Structure Simulator (HFSS) platform. The simulation outputs are internally compared with different iterations implemented on the patch using Iterated Function System (IFS) and the difference in the radiating frequency, return loss, bandwidth, gain and directivity of all three different iterations. The resonating frequency for three iterations ranges from 5.8GHz to 7.47GHz which can be used in WLAN applications. Thus, the proposed Koch snowflake fractal antenna design provides improvements in the antenna parameters on increasing scale of iteration such as S11 from -21.35dB to -36.32dB, average gain of 3dB and Impedance Bandwidth of 25.90%.