Patent attributes
An apparatus, comprising: a transmitting coil; a first receiving coil having a first receiving coil portion and a second receiving coil portion, the first receiving coil portion and the second receiving coil portion being coupled to one another, and the first receiving coil portion and the second receiving coil portion each including N lobes, where N is an integer and N≥1; a second receiving coil having a third receiving coil portion and a fourth receiving coil portion, the third receiving coil portion and the fourth receiving coil portion being coupled to one another, and the third receiving coil portion and the fourth receiving coil portion each including N lobes; wherein the first receiving coil is disposed over the second receiving coil.