A 3.7-4.3 GHz frequency modulated ultra wideband (FM-UWB) transceiver with digitally reconfigurable subcarrier modulation index, UWB bandwidth and RF frequency band is fabricated in 0.18 μm CMOS. Considering short-range low-data-rate applications for wireless body area networks, RF front ends, consisting of an output amplifier with -14 dBm power level, an FM demodulator with -35 dBm sensitivity, and a preamplifier with 25 dB gain, 6 dB noise figure, are designed. The presented implementation including UWB bowtie antennas achieves a bit error rate (BER) of 10-6 at a data rate of 12.5 kb/s with a wireless communication distance of 60 cm and the power dissipation of 21 mW.