Footwear and wrist communication links using 2.4 GHz and UWB antennas

It is reported that wearable electronic devices are to be used extensively in the next generation of sensors for sports and health monitoring. The information obtained from sensors on the human body depends on the biological parameters, the measurement rate and the number of sensors. The choice of the wireless protocol depends on the required data rates and on system configurations. The communication link quality is achieved with narrowband technologies such as Bluetooth or Zigbee, provided that the number of sensors is small and data rates are low. However, real-time measurements using wideband channels may also be necessary. This paper reports narrowband link performance at 2.45 GHz for comparison with two UWB channels centered at 3.95 GHz and 7.25 GHz. A monopole antenna covering 2.45 GHz and UWB is optimized for an on-body communication link between the footwear and the wrist. The cumulative distribution function of several path loss measurements is reported and compared for a subject standing and walking. Results show that the larger bandwidth in the UWB channel reduces fading and stabilizes the channel predictability.