Notch band optimization of planar Ultra Wide Band antenna using GA Anju Pradeep, Shameena V.A, S.Mridula, Binu Paul & P.Mohanan Centre for Research in Electromagnetics and Antennas Cochin University of Science and Technology Kochi – 682 022, India email: drmohan@ieee.org Abstract The paper presents the optimization of the notch band in an Ultra Wide Band (UWB) serrated monopole antenna using a modified Genetic Algorithm approach. The results are compared with that of a similar antenna where the slot is designed using conventional approach. The algorithm is found to be highly efficient in terms of computation time and slot area. 1. Introduction Ultra Wide Band (UWB) antennas are capable of high data transmission rates and can be used in communication applications such as RFID devices, sensor networks, radar and location tracking requiring small size and non dispersive properties. Its commercial usage of frequency band from 3.1GHz to 10.6GHz was approved by the Federal Communications Commission (FCC) in 2002. UWB antennas should reject interference with existing wireless networking technologies such as IEEE802.11a in the U.S. (5.15-5.35GHz, 5.725-5.825GHz) and HIPERLAN/2 in Europe (5.15-5.35GHz, 5.47-5.725GHz) [1]. This is important because UWB transmitters should not cause any electromagnetic interference on nearby wireless LAN systems. Therefore, UWB antennas with notched characteristics in WLAN frequency band are desired. The ability to provide this function can relax the requirements imposed upon the filtering electronics within the wireless device. 2. The planar UWB antenna The geometry of the planar Ultra Wide Band antenna chosen for notch band optimization is shown in Fig. 1. The antenna operates from 3.5GHz to 12GHz [2]. The monopole has a staircase edge, with a mirror image geometry on the ground plane with an offset of 2mm along y-direction. This geometry increases the edge dimensions and provides improved bandwidth due to multiple resonances as explained in [2].The antenna radiates with good return loss in the W-LAN frequency (5.1GHz to 5.82GHz). To avoid this interference, a notch band at these frequencies is desired. The paper deals with the optimization of the slot in the antenna to achieve the above desired radiation characteristics. Fig. 1 UWB antenna chosen for optimization of notch 3. Genetic Algorithm Optimization Genetic algorithm is an effective tool for optimizing the antenna design to achieve required radiation characteristics of antenna. In order to overcome the inherent slow convergence feature of conventional approach in