Em wave incident on a surface current

metalrose

Consider an infinite sheet of surface current described by the surface current density , K=dI/dl, where dl is a length element perpendicular to the current.

For this sheet, the magnetic field B=μK/2, above and below the sheet, independent of the distance from the sheet, where μ is for free free space.
The dirction of B is parallel to the sheet and perpendicular to the current flow.

Now if a plane em wave approaches such a surface, does the B vector of the em wave always satisfy the above equation, independent of seperation from the sheet?

I doubt so, since the magnitude of the B vector of the em wave depends on the source of the wave.

But if B vector of em wave doesnt satisfy the eq. B=μK/2, then B has values different from this value, above and below the sheet, which would be inconsistent with the amperes law, using which B=μK/2 has been derived for the sheet in the first place.

Where am i going wrong ??