Performance analysis of ultra small antenna in body-air channel

We propose a new slab shaped body-air channel model, in which the transmit antenna is located in body while receiver is placed in the air. The signal strength received at an ultra small magnetic dipole TX antenna is analyzed using wave equation, simulation, and experiment. Due to the slab reflecting effect, the results surprisingly show that there exists an optimum transmit antenna location in body which makes the receiving power maximum. Notably, the signal strength from a TX antenna located 7-8cm underneath is equivalent to that at the body surface and 8dB higher than the minimum case.