- VTT Technical Research Centre of Finland
In this work we present a systematic methodology for realizing desired sheet impedances of printable metasurfaces. This methodology allows independent control of the sheet reactance (capacitance and series inductance) and its resistance, even if the conductor properties as well as the dielectric substrate thickness and permittivity are fixed due to manufacturing process restrictions. The derived analytical formulas allow us to easily find the physical dimensions of conductive patterns which implement the required surface impedance. Numerical verification of the method shows excellent agreement with the analytical predictions, allowing the design of an arbitrary impedance without any optimization process. The method can be applied for designing lossy and low-loss metasurfaces which can be used for absorption and wavefront manipulation of electromagnetic waves. As a representative example, the design of thin perfect absorbers has been approached using the developed method. The results demonstrate that the methodology adapts various material sheet resistivity, opening new possibilities for the design of printable metasurfaces where the sheet resistivity of conductor strongly depends on the specific printing method. Finally, an experimental validation of absorbers designed for millimeter waves and printed using reverse-offset techniques is presented. To the best of authors’ knowledge, this is the first time when reverse-offset printing has been used to provide well-working devices for short millimeter waves.