Microwave Magnetic Field Imaging Using Thermo-Emissive Ferromagnetic Micro-Structured Films

A new microwave magnetic field measurement method based on infrared emission is presented. This method uses thin patterned ferromagnetic films sputtered on polymer substrates. The incident field interacts with the film and is responsible for ferromagnetic losses that create local heating. This heating is recorded by an infrared camera, providing magnetic field pattern images and amplitude evaluation. Moreover, the tangential components of the H field can be identified thanks to the anisotropic structure of the sputtered film. The large permeability NiFe based thin films were grown using a sputtering method and complex permeability measurements have been carried out in the microwave range. Both infrared pictures and magnetic permeability measurements are presented and correlated.