Computing two physics models Simultaneously

Hello,

I am trying to combine MAGNETIC FIELD physics with Electromagnetic Waves, Frequency Domain physics for a Helmholtz coil application. In middle of coils is a FR4 board with transmission line on it. I need to encase this board in a perfect electric conductor block. This where I need the Electromagnetic Waves, Frequency Domain physics.

However, I can never get both the models to work together. Infact, Electromagnetic Waves, Frequency Domain never gets computed in the presence of Magnetic field physics.

Can anyone suggest anything?