Yes, that's true. Electromagnetics are part of solid state physics. I think there is a tradition to it too, as solid state electronics came to be about semicond

Yes, that's true. Electromagnetics are part of solid state physics. I think there is a tradition to it too, as solid state electronics came to be about semiconductors, and I think still to this day, solid state has that connotation. For that reason I see no problem in calling this a solid state device.