Ultra-low-profile low frequency antenna

An ultra-low-profile low frequency antenna including a magnetic core having coil winding channels in three intersecting axial directions orthogonal to each other, defining X-axis (X), Y-axis (Y) and Z-axis (Z), receiving respective X-coil (DX), Y-coil (DY), and Z-coil (DZ). A Z-coil winding channel surrounds the magnetic core around the Z-axis (Z), providing partial grooves confined between two parallel surfaces. The thickness of the magnetic core in the Z-axis (Z) is less than 1.2 mm. Each partial groove has a width in the Z-axis (Z) equal or less than 0.4 mm and its depth in a radial direction perpendicular to the Z-axis (Z) is at least two times of its width. The Z-coil (DZ) is wound within said groove and extends radially from ⅓ to ⅔ of the groove's depth. The outer edge of the Z-coil is at the entrance of the groove.