  When the electrically thin unit cell of a laminated composite material is
made of two bianisotropic sheets whose constitutive properties in the thickness
direction are decoupled from the constitutive properties in the interfacial
planes, the laminated composite material can be homogenized into a material not
all of whose constitutive parameters are independent of each other. This
non-independence of the constitutive dyadics of the constituent materials and
the homogenized composite material is captured by two simple constraints, which
may not hold if even one of the two constituent materials has more complicated
constitutive properties than stated above.
