Terahertz electromagnetic field propagation in human tissues: A study on communication capabilities

A Body Area Nano-NETwork represents a system of biomedical nano-devices that, equipped with sensing, computing, and communication capabilities, can be implanted, ingested, or worn by humans for collecting diagnostic information and tuning medical treatments. The communication among these nano-devices can be enabled by graphene-based nano-antennas, which generate electromagnetic waves in the Terahertz band. However, from a perspective of the electromagnetic field propagation, human tissues generally introduce high losses that significantly impair the communication process, thus limiting communication ranges. In this context, the aim of this contribution is to study the communication capabilities of a Body Area Nano-NETwork, by carefully taking into account the inhomogeneous and disordered structure offered by biological tissues. To this end, the propagation of Pulsed Electric Fields in a stratified media stack made up by stratum corneum, epidermis, dermis, and fat has been carefully modeled. First, electric and magnetic fields, as well as the Poynting vector, have been calculated through an accurate Finite-Difference Time-Domain dispersive modeling based on the fractional derivative operator. Second, path loss and molecular absorption noise temperature have been evaluated. Finally, channel capacity and the related transmission ranges have been estimated by using some baseline physical interfaces. Moreover, the comparison with respect to reference values already available in the literature is presented too. Obtained results clearly highlight that new research efforts are needed to ensure the considered communications due to the severe impairment suffered by electromagnetic waves.