High voltage breakdown analysis of nickle-zinc ferrite double-positive metamaterials

Metamaterials are currently under development to reduce the size of high power antennas. These materials may also have applications in other high power, dielectric-loaded components, including nonlinear transmission lines. A new procedure has been developed at the University of Missouri-Columbia that produces a double-positive metamaterial by combining nickel-zinc ferrite powders with a dielectric binder. The resulting composite is a machinable bulk material produced at significantly lower temperatures than sintered components. Previous measurements have shown this material to possess positive relative permeability and permittivity values in the range of 4 to 6 for frequencies between 200 MHz and 2 GHz. The dielectric strengths of five different types of ferrite-based composites were measured to evaluate the potential of these materials for high power applications. A pulser with a magnitude up to 100 kV and rise time on the order of tens of nanoseconds was used to determine the dielectric strength of disks with a diameter of 2.54 cm and a thickness of 2 mm. This work presents a statistical analysis of the dielectric strength data and projects the power handling capabilities of the composites.