Fully inkjet-printed multilayer microstrip and T-resonator structures for the RF characterization of printable materials and interconnects

A vertically-integrated, fully inkjet-printed microwave structure is demonstrated for the first time, where both the metallic elements and the platform substrate are completely fabricated with the additive inkjet printing process. The surface uniformity of SU-8 polymer ink is outlined as a function of layer deposition to provide a desirable profile for a thick RF substrate application. Inkjet-printed vias are demonstrated and realized as microwave substrate interconnects within SU-8. Microstrip and T-resonator structures are developed to demonstrate the application of these inkjet-printed platforms for the RF characterization of a printable material, where the relative permittivity of the substrate is extracted as a function of frequency from 1-30 GHz.