Comparison of directlional and omnl-directlonal UWB antennas for Wireless Body Area Network applications

In this paper we present a low-profile directional UWB antenna with improved radiation efficiency when operating in close vicinity to a biological tissue. This antenna is intended for the use in UWB wireless body area network (WBAN) applications, between 3 and 6 GHz. A novel design is based on a UWB slot antenna structure with an added radiator/reflector element in order to achieve directional radiation pattern. We compare results of our novel design, to those of the omni-directional UWB monopole antenna (currently the most commonly used in UWB studies). Measurement and simulation results show that the developed directional UWB slot antenna has the improved radiation efficiency in the vicinity of human body. Moreover, proximity of the human body much less influences its transfer functions (the most important antenna parameter in UWB radio), compared to the omni-directional UWB monopole antenna