International Journal of Computer Applications (0975 – 8887) International Conference and Workshop on Emerging Trends in Technology 2014 33 Design of Dome Shape Slot Antenna for UWB Applications Vivek Kamble M. Tech. Student Depart. of Applied Physics DIAT(Demmed University) Girinagar, Pune-25, India Raj Kumar Armament Electronics ARDE, Pashan, Pune-411 021, India Praveen Naidu Research Scholar Symbiosis Int. University Pune-411 046, India ABSTRACT In this paper, a compact micro strip fed dome shape slot antenna for Ultra Wide Band (UWB) applications is proposed. The dome shape is obtained by rounding (blending) the corners of a hexagonal slot. To excite the slot, a micro strip feed and a rectangular shape tuning stub is used. One of the corners of the rectangular patch is chamfered while the others are blended for better impedance matching and return loss. The patch and the ground plane are printed on the opposite sides of an inexpensive FR4 substrate with overall dimensions of 24 mm × 35 mm. The experimental result shows that the proposed antenna has good impedance bandwidth of 10.9 GHz from 2.14 GHz to 13 GHz (143%) which covers the entire UWB Band. The stable radiation patterns which are nearly Omni directional in H-plane and dumbbell shape in E- plane have been achieved. Keywords Antennas, Slot antenna, CPW-feed, Ultra wideband (UWB) and UWB Systems 1. INTRODUCTION UWB is a short distance radio communication technology which is having many advantages like wider bandwidth, low power output and high data rate (more than 100 Mbps) when compared with traditional communication systems. Because of these advantages, a lot of interest has been generated in researchers and engineers for the development of UWB antennas for short-range wireless, imaging radar and remote sensing applications. Also various characteristics of ultra wideband (UWB) technology like low cost, low complexity, low spectral power density, high data resolution, very low interference, and extremely high data transmission rates have made it a potential candidate in various wireless communications. Researchers have proposed many slot antennas for UWB applications. Among the planar UWB antennas, the printed slot antenna is one of the most suitable candidates for UWB applications. The wide-slot antenna always gives wider impedance bandwidth it is seen that large antenna slot dimension makes impedance bandwidth wider [1]. Study and optimization of microstrip feed lines of various shape exciting Rectangular slot is proposed in [2-5]. CPW fed UWB wide slot antennas are optimizes and proposed in [6-9]. In an approach presented in [10],. A Effect of similar ground and Patch shapes is studies and a wide band antenna using this approach is proposed in [10] E shaped Patch and E shaped ground slot is studied and optimized in this antenna which achieves an impedance bandwidth of 120% (2.8–11.4 GHz). However, Due to large dimensions 85mm × 85 mm. this antenna cannot provide compact profile Different tuning techniques, various patch shapes and their Applications is studied and optimized in [11]- [12] and introduction of new but unconventional shape , a rhombus shaped slot is presented in [13]. The antenna proposed in this paper has the advantage of compactness in size with wide bandwidth. It uses a dome shape slot which is excited by a micro strip feed line with a rectangular tuning stub. Suitable blending and chamfering of the slot and patch corners gives the ultra wideband characteristics. 2. ANTENNA DESIGN The antenna geometry and configuration is shown in Fig. 1. The antenna consists of a dome shaped slot etched in the ground plane and a micro strip line fed, chamfered rectangular patch for excitation. The slot and rectangular patch are printed on opposite sides of an inexpensive FR4 substrate of thickness 1.6 mm and relative permittivity 4.3. The slot in the ground plane has a strong coupling to the feeding structure. Therefore, by properly selecting the shape of the slot and patch, good impedance bandwidth and radiation characteristics can be achieved. The optimized parameters of the proposed antenna are mentioned in Table 1. The overall size of the antenna is 24 mm × 35 mm. The feed line has a width of 2.8 mm. The development of the dome shape slot is shown in Fig. 2. The slot is initially hexagonal in shape, rectangular patch .the patch was taken symmetric in shape as shown in figure 2(Reference antenna) laterally for improvement in return loss the asymmetric design (Reference Antenna 1) of patch is chosen which has an advantage of better return loss characteristics as shown in figure 3, The radius of the blend in ground plane is denoted by equal to 6mm. Similarly, the rectangular patch has its edges blended by arcs of radii 3mm. Also one of the corners of the patch is chamfered. This parameter is denoted by Pc in Fig. 1 and has an optimized value of 9.2 mm. The improvement in the return loss with these modifications is shown in Fig. 3 where a comparison with the antenna with unblended slot and patch (Reference Antenna) is made.