Excitation and propagation of waves on human arm models

This paper investigates scenarios of wireless transmission on human arm models. Two different arm models are considered: a PMMA pipe filled with muscle-tissue simulating liquid is used for both simulations and measurements, and a three-layer model whose geometry was obtained from a magnetic-resonance imaging (MRI) scan of a human arm is considered in simulations. Numerical simulations and measurements are carried out at a frequency of 4.1 GHz. Waves coupling transmitter and receiver are most efficiently excited by monopole-like radiators oriented perpendicularly to the surface. Efficient excitation is also possible by dipole-like radiators oriented parallel to the surface and aligned with the direction of wave propagation. Note that in this case, the dipole far-field pattern has a null in the direction of propagation. The worst excitation is obtained by dipoles parallel to the surface and oriented transversely to the propagation direction. All results support the finding that surface-wave like propagation occurs along and around the human arm, and efficient excitation of these waves can be achieved by antenna near-fields.