Abstract

This letter reports the shadowing effects of a human body on dynamic ultrawideband on-body radio links. A vector network analyzer is used to sweep the 3–5-GHz frequency band in an anechoic chamber. The sweep time is set fast enough to fulfill the channel coherence time requirements. This enables the data analysis to be performed in time domain by examining the corresponding channel impulse responses. Five on-body locations are examined: right wrist (RW), left wrist with an antenna on the palm (LWA) or back side of the hand, left arm, and left ankle (LA). Two antenna types are applied: dipole and double loop. The path loss (PL) lies between 35.9 and 85.8 dB depending on the case. The double loop has, on the average, higher PL than the dipole. The LWA-RW and RW-LA links have the lowest and highest PLs, respectively. The amplitudes of the first arriving paths follow the inverse Gaussian distribution. The level crossing rate (LCR) and the average fade duration (AFD) show weaker performance for the double loop antennas compared to the dipoles. In general, the LWA-LA is the poorest link with respect to the LCR and the AFD.