Microfabrication of high permittivity metamaterials with tall metal inclusions in thick photoresist layers

Inhalt:
Microfabrication of dielectric metamaterials with tall embedded metal inclusion grids in thick resist layers is demonstrated. Deep X-ray lithography is used to realize cavities with aspect ratios up to 50:1 in polymer resist layers up to 1.6 mm thick. Nickel electroplating is used to fill the cavities to realize inclusion elements up to 800 µm in height, forming the embedded metal grid. The embedded grid structure causes an increase in the effective relative permittivity of the polymer resist layer by a factor of up to 4-6, resulting in an artificial material with controlled dielectric properties that is useful for emerging applications at microwave and millimeterwave frequencies.