An FM-ultra-wideband (UWB) system with a wideband RF carrier (WRC) is proposed for wireless body area network applications. The proposed system can control the channel power by means of an adjustable carrier bandwidth (BW), while the conventional one with a CW carrier (CWC) makes use of peak power control. The implemented WRC system performances have been evaluated for the WRC generation and digital data transmission. In addition, transmission performances have been compared with that of a conventional CWC system by bit-error-rate (BER) tests. For random data of a 29−1 pattern at a data-rate of 64 kbps, in spite of the flexible carrier BW, the WRC system has presented excellent transmission capability compared with that of the CWC system.