High frequency circuits for wireless, digital and microwave applications place requirements upon the impedance of their signal lines, interconnects and packaging. In designing and implementing the substrates for these signal lines it is beneficial to employ meta-materials to provide the desired impedance. Such meta-materials providing a means to provide modified permittivity and permeability for the substrate, these being different than the real permittivity and permeability of the insulator used. In an example embodiment, a substrate is configured as a meta-material. It is desirable therefore to have a means to model these meta-material aspects of the signal lines rapidly and accurately allowing the circuits, interconnects and packages to be designed and implemented without expensive and exhaustive iterative experimental characterization. Within the cited invention design parameters for the meta-material structure are determined in dependence upon input parameters characterizing the conductive medium, dielectric medium enveloping the conductive material, and the pre-determined shapes of the conductive medium.