Most modern underwater drones (UDs) employed in military and environmental monitoring operate in the ocean and are conceived as intermediary transceivers between their base station (BS) and underwater wireless sensor networks (UWSNs). Due to the salinity and consequently the conductivity of seawater, UDs cannot use conventional radiofrequency (RF) transmissions, either for powering or communicating with the sensor nodes (SNs). Trying to overcome these limitations, inductive power transmission (IPT) systems have been pointed out as an alternative for reliable UD-assisted UWSNs. IPT presents lower losses than far-field-based techniques in complex media but is extremely limited in terms of operating distance. Based on that, the present thesis aims an all-integrated solution for UD-assisted monitoring systems based on IPT systems using metamaterial (MTM) lenses and reflectors dedicated to improving both the power transfer efficiency and the signal-noise ratio of the transmitted data. A new model of the magnetic channel, based on the virtual magnetic transmission line model, incorporating the MTM gains and the seawater losses, is also presented in order to facilitate the future systematization of UWSNs.