In this paper a spline-shaped monopole radiator for utilization in Ultrawideband (UWB) Wireless Body Area Networks (WBANs) is presented. The antenna exhibits a good impedance matching and stable radiation patterns in the lower UWB band from 3.1 to 4.8 GHz. Moreover, it shows distortion-less properties when used in a chest-to-waist communication link. In order to assess the effectiveness of the proposed solution, both numerical and experimental results are reported.