A magneto-inductive transmit antenna is provided that includes a shield formed of a magnetic material, a magnetic field source mounted on a first side of the shield, and a coil wrapped around the shield to define a number of turns. The coil is configured to conduct a current therethrough. The magnetic material is configured to exhibit a change in permeability based on the current conducted through the coil when the current is conducted through the coil. The change in permeability is configured to modulate a magnetic field of the magnetic field source. The magnetic field is modulated relative to a second side of the shield opposite the first side when the permeability is changed.