Composite screen with magnetic-field-controlled radio transparency

The effect of static magnetic field on dielectric spectra (in a frequency band of 6–12 GHz) of plane composite sheets filled with amorphous microwires made of Fe and Co alloys is studied in experiments and with the aid of computer simulation. Two intervals of the dependence of permittivity on the external static magnetic field are analyzed. The effect at relatively strong fields (800–1000 Oe) is related to the dependence of the parameters of ferromagnetic resonance (FMR) on the external field, and the effect in the presence of weak fields (about 100 Oe) is due to the rearrangement of the domain structure of Co microwire. The analysis of relation of magnetic impedance and dipole resonance in fragments of microwire is used to determine the effect of the FMR parameters, diameter and length of wire, and the structure of composite on the dielectric spectrum of the composite sample. The results are used in the study of screens with tunable radio transparency.