Characterization of phantom size and link budget for off-body communications

This paper presents a characterization of on-body antennas for off-body communications on a minimal size phantom, which is still representative of the whole human body at two different frequencies. Two equivalent PIFA antennas have been designed at different scales to study the body impact at RFID 868 MHz and ZigBee-Bluetooth 2.45 GHz bands. The antennas are properly retuned when placed on the phantom with the average gains on the horizontal plane of −0.93 dBi and 0.16 dBi respectively. This indicates that the body impact is negligible in this case. However, the link budgets at these two frequencies show their different features in physiological parameters monitoring applications.