Ground plane directly underneath physically large 100 µH inductor?
Looking at the inductor, it is a bobbin type, but the datasheet does not state whether it is a shielded type (1).

There is, however, a clue:

The datasheet states:


  The 1400 Series is suitable for many power supply and other general
  purpose filtering applications. The use of a non-magnetic screw will
  ensure mechanical stability


Highlight mine.

That seems to imply that the part is not shielded (otherwise a non-magnetic screw would not be suggested), so my instinct would be to void everything underneath the inductor.


Shielded inductors are not fully shielded; the H field is suppressed, to be sure, but never eliminated; this can bite the unwary very hard, particularly in SMPS layouts. Toroidal cores are superior in this regard but become unwieldy at large inductances,
.