Design of fractal antenna for WLAN and UWB applications

Abstract

The wireless revolution is transforming the existing global telecommunications networks into an integrated system that will provide a broad class of ubiquitous communications services to customers anywhere, anytime, in motion or fixed. Antenna is an important device in WLAN communication system because its performance will directly impact on the quality of wireless communications. The continuous decrese in the size of electronic equipments demands smaller size antenna elements so that they can be properly fit in wireless devices without compromising the other radiation properties of the antenna. In this respect fractal antennas are quite an obvious choice. This project started by identifying two main disadvantages of the typical microstrip antenna that are the low gain and narrow bandwidth. These two major drawbacks have limited its application despite of other advantages as compared to the conventional antenna. Several antenna configurations were proposed and from the simulation result, the antenna bandwidth was improved from the typical 8 ~ 9 % up to 36 % by using these two techniques using a simple coaxial probe feeding without any matching network. A fractal antenna consists of radiating patch placed on the dielectric material eith self repetating structure.feed line used is microstrip feedine technique . The different types of slots on the patch and the stacking help in increasing the bandwidth and give the efficient results. In this thesis report various antenna designs are given and then study the various effects of different parameters like patch length, patch width, substrate height, and dielectric constant for WLAN applications. The antennas are designed using CST 2014 microwave studio. The antenna parameters like return loss, bandwidth, resonating frequency, directivity, gain and VSWR are calculated for each antenna design in order to get the best antenna.