Dielectric Permittivity Measurement of Paper Substrates Using Commercial Inkjet Printers

Commercial inkjet-printers from manufacturers like Epson or Brother can be used for rapid prototype printing conductive traces onto paper or flexible PET substrates by using nanoparticle based dispersions. The surface coating of the substrate influences the attainable electrical conductivity and dielectric permittivity as well as the loss tangent, which are important parameters for developing inkjet-printed microwave circuits on paper substrates. For characterizing the permittivity conventional methods are using microstrip ring or microstrip transmission line resonators that require the printing of two electrically conductive layers. In the proposed paper, a novel method is introduced to determine the relative permittivity and loss tangent via a coplanar waveguide resonator realized on a single layer.