Inductive proximity switch and method for sensing objects

A method, comprising:

• generating an alternating magnetic field using a transmission coil, wherein the transmission coil has turns formed on a first circuit board and includes a first primary winding having a first winding direction;
• and
• sensing, using a first sensor coil and a second sensor coil, a change in the magnetic field caused by proximity of an object, wherein
• the first sensor coil has turns formed on a second circuit board and includes a second primary winding having a second winding direction,
• the second sensor coil has turns formed on a third circuit board and includes a third primary winding having a third winding direction opposite to the second winding direction,
• the transmission coil, first sensor coil and second sensor coil are spaced apart from one another in a common axial direction,
• at least one of the transmission coil, first sensor coil and second sensor coil includes a compensation winding having at least one turn,
• the compensation winding is arranged radially outside of, and has a winding direction opposite to, the same coil's primary winding;
• at least the transmission coil and one or both of the sensor coils is formed as a group of parallel coils arranged in parallel layers;
• and
• a number of layers in the transmission coil is at least as high as a number of layers in either the first or second sensor coil.