Terahertz Intra-body Propagation through LOS and NLOS Links

In this paper, we propose a theoretical intra-body propagation model for signal transmission in the THz frequency band. The channel of interest is a blood vessel composed of red blood cells (RBCs), where propagation occurs between a nanoantenna transmitter and a protein receiver. The presented model accounts for signal losses due to molecular absorption and scattering through both line-of-sight (LOS) and non-line-of-sight (NLOS) links. The RBCs between the antenna and the protein act as obstacles that attenuate the signal power giving rise to shadowing. By conducting Monte Carlo simulations, we develop the random characteristics of the transmission medium. Inspired by radar systems, an expression for the received power is derived using the bistatic radar model and the total path loss is computed through the different links. The results are validated by means of electromagnetic wave propagation simulations. The presented work indicates that a reliable communication link exists between the nanoantenna and the protein through both the LOS and NLOS transmission. Our work facilitates the accurate design of in-vivo wireless nanosensor networks and paves the path towards selective intra-body interactions.