The ultra wideband antenna design for UMB system

Abstract

Since a technique of Ultra WideBand(UWB) system had been developed, there has been rapid growth in this area. But, non license-UWB system development brings a dispute about the admission of the frequency band overlapped in the previous commercial band. However, FCC``s approval on the UWB band in 2002 finished the controversy. Nowadays, the UWB systems are being itemized rapidly, and the wireless speed will increase suddenly. Since the UWB antenna demand also increase, we need to modify existing antenna model or to develop a new wide band antenna. So, this paper presents the design method of the ultra wide band antenna without dimension change, and impedance transformer antenna using a coplanar waveguide. First, the double discone antenna shows ultra 30:1 wide bandwidth from 265 MHz to 9.6GHz below VSWR 2.5. And the radiation pattern is same the conventional discone antenna. This antenna can be used as a frequency monitoring antenna for military use, as a commercial wireless band antenna, and as a UWB system antenna. But, this antenna is needed to study their disk size or cone surface bending shape in order to show horizontal radiation pattern. Secondly, the proposed coplanar waveguide antenna shows 1:7 bandwidth ratio, which covers 900MHz system and commercial band, and UWB system band. And the small and slim size advantage makes the antenna use indoor wireless system and to be applied in the hand phone set by reducing the size. The proposed two antennas are considered as good antennas in the forthcoming UWB communication situation.