Polarisation ellipses and magnitude of the magnetic field produced by a transmitter coil of radius of r₀ = 11 mm when a coaxial receiver coil displaced by 37 mm, and two coils are insulated by two cylindrical dielectric boxes with the height 2h = 7 mm. Ellipse axes are normalised and plotted at a sampling step of 2 mm along the y and z directions. Black dash lines mark the cross sections of the dielectric boxes. The conductivity of the block is σ = 10 S/m. The mutual inductances is M = 0.11∠ −122 °.