Determining the dots (signs) in a planar transformer

[nikogian]

Hi all,
Can someone tell me how can I determine the dots (i.e how the current flows) in the primary an secondary coils of a planar transformer? Is there a safe way to figure them out or I need to use EM simulation?

Thanks

 

[FvM]

It's the same as with any transformer. Two windings with equal polarity have equal voltage sign and opposite current sign. As given by elementary electromagnetic rules.