First results in the development of double-positive metamaterials for high power microwave components

A new research effort at the University of Missouri-Columbia aims to develop metamaterials for high power antennas and other microwave devices. In the past, size reduction of high power antennas has focused on the development of materials with a high relative permittivity. However, the authors propose that by controlling both the permittivity and permeability, it will be possible to significantly reduce the component size while also optimizing the impedance for improved efficiency and bandwidth over previous designs that used only a high relative permittivity. This could lead to improved performance for various loaded antennas, as well as benefits to other microwave devices incorporating insulating material with an optimized impedance. Using techniques developed at the University of Missouri-Columbia for the production of high dielectric constant composite materials, initial metamaterial samples have been produced by insulating ferrites and binding them into a composite matrix. The initial stage of this project investigated taking a variety of ferrites and measuring their properties once incorporated into a composite. These ferrites ranged from having a relative permeability of 1200 at 200 MHz to 50 at 800 MHz. Permittivity and permeability measurements of initial samples indicate wavelength and impedance optimization via metamaterials is feasible.