Characterisation of properties of conductor-backed MagRAM layer using reflection measurement

A technique for characterising the thickness and the complex permittivity and permeability of a conductor-backed layer of magnetic radar absorbing material (MagRAM) is presented. Instead of determining these parameters directly from measurements, an a priori relationship between the material parameters and the loading fraction of the magnetic particles in the material is utilised, and the loading fraction is determined. This may be accomplished using a single swept-frequency measurement of the reflection coefficient, in contrast to existing techniques that require reflection measurements made under two independent conditions. Experimental data is used to demonstrate the feasibility of the technique, and explore the inherent uncertainty in the method.