High-performance matched absorber using magnetodielectrics
AssigneeNorthrop Grumman Corporation
InventorsRodolfo E. Diaz, Michael C. Miller, Michael M. Lo Re', James P. K. Gilb, Shahriar Alam
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Abstract
A composite electromagnetic absorber provides increased EMR absorption while being thinner and/or lighter than prior art EMR absorbers. To accomplish this, synthetic dielectric materials are combined with either synthetic magnetic materials or magnetically lossy materials in such a way that the permittivity and permeability of the composite material are substantially matched over the desired range of frequency. The match in the permittivity and permeability allows the majority of the electromagnetic fields to enter the material where the electric and magnetic loss components absorb the electromagnetic energy.
Claims4
A method for electro magnetic wave absorption by a synthetic absorption material, the method comprising the steps of:
- (a) choosing a frequency band;
- (b) mixing magnetic metal coated microspheres in a dielectric matrix, the magnetic metal coated microspheres having a magnetic loss, dimensions for the magnetic metal coated microspheres and a 3-dimensional arrangement for the metal coated microspheres being selected so as to provide a desired magnetic permeability within the chosen frequency band;
- (c) disposing a lower layer of metal coated microspheres in a dielectric matrix upon a supporting surface;
- and
- (d) disposing an upper layer of magnetic metal coated microspheres in a dielectric matrix upon said lower layer, wherein said upper layer has a density of the magnetic metal coated microspheres less than the density of the magnetic metal coated microspheres in the dielectric matrix of the lower layer.
Dependencies are inferred from the claim text.