LDC0851: Stacked Coil and Side-by-Side Coil

Yes, you can experiment with different shapes of coils. We have found that the circular coil is the most optimum for inductance in a tight space and sensing distance. That being said, there are applications where other shapes are desirable.

Janine,

I answered the keepout question on a different thread you posted.

Note that the primary factor for sensing distance is the shortest measurement across a coil. This means that a long thin coil will not get that much better of a response than a circular coil of the same width. Of course, if your target has to be shaped that way, then there is merit to stretching the coil to cover more of the target area.