a metallized substrate , such as used to make a resonant circuit tag with inductive and capacitive elements in series , has a thin inorganic or polymeric dielectric layer formed on a metal layer . the inorganic layer may be formed by anodizing a surface of the metal layer . the organic layer may be formed by flexographic printing . in both cases , a via hole is formed through the dielectric layer . a second layer of very thin conductive metal is deposited on the dielectric layer and in the via hole . the substrate is subsequently patterned with an etch resist and then etched to form the inductor coil and the capacitor plates , which are interconnected via the metallized via hole .