B13. Design of Notched Ultra-wideband Antenna with Irregular Radiator Shape Using Bacterial Swarm Optimization (BSO) Algorithm

Abstract

In this paper, the Bacterial Swarm Optimization (BSO) is linked with the Finite Element Method (FEM) simulator (Ansoft HFSS simulator) to design a notched ultra-wideband antenna with an irregular shape radiator for ultra-wideband (UWB) applications. The proposed antenna has a compact substrate size of 30 mm by 30 mm and 1.6 mm thickness. The optimized antenna can cover the spectrum of UWB (from 3.1 GHz to 10.6 GHz) with notched band from 5 GHz to 6 GHz for WLAN service (5.15-5.825 GHz) achieved by attaching U-shape slot on the radiator element. The results are compared with that calculated by the Finite integration technique (FIT) method and with the measured results. Good agreement is obtained. The proposed antenna shows acceptable gain flatness with stable omnidirectional radiation patterns across UWB bands. Keyword: UWB-BSO-FEM-FIT-notched UWB. INTROUCTIONRecently, ultra-wide band (UWB) technology has been attracting much attention for communication systems especially since the U.S. Federal Communications Commission (FCC) began allowing use of the band from 3.1 to 10.6 GHz for commercial applications [1]. UWB systems have widely been exploited in the wireless short-range high throughput communication operating over the same frequency range. To satisfy such requirement, various UWB antennas have been studied [2][3]. Planar monopole antennas are very suitable for UWB applications [4]. However, due to the overlap of currently allocated UWB frequency band with the existing wireless local area network (WLAN) (5.15 -5.825 GHz), special characteristics such as band notch are much desired for UWB antennas to reduce the interference between those two communication systems [5][6]. Accordingly, an ultra-wide band antenna with a band-notch characteristic can be an alternative choice to the use of a distinct stopband filter in the system. One simple way is to etch thin slots in the antenna surface [7] to achieve the band-notched characteristic.During the last decades various optimization techniques like Genetic Algorithm (GA), and Particle Swarm Optimization, in addition to many hybrid optimization methods have been used for optimizing parameters in the antennas and antenna array problems [8][9][10][11][12]. Another method known as Bacteria Foraging Algorithm (BFA) that is based on the foraging behavior of Escherichia Coli (E. Coli) bacteria present in the human intestine [13] has already been used to many engineering problems including antenna design and antenna arrays [14][15][16][17]. In [18], the BFA is oriented by Particle Swarm Optimization (PSO) to combine both algorithms' advantages, which is called the BSO algorithm. This combination aims to make use of the PSO ability to exchange social information and the BFA ability in finding a new solution by elimination and dispersal [19][20]. It is found that, the overall performance of the BSO algorithm is definitely better than the stand alone BFA on the numerical benchmarks tested and at least comparable with PSO and its variants. In [21], a hybrid approach involving Bac...