Fabrication of Fully Inkjet-Printed Vias and SIW Structures on Thick Polymer Substrates

In this paper, a novel fully inkjet-printed via fabrication technology and various inkjet-printed substrate-integrated waveguide (SIW) structures on thick polymer substrates are presented. The electrical properties of polymethyl methacrylate (PMMA) are thoroughly studied up to 8 GHz utilizing the T-resonator method, and inkjet-printable silver nanoparticle ink on PMMA is characterized. A long via fabrication process up to 1 mm utilizing inkjet-printing technology is demonstrated, and its characteristics are presented for the first time. The inkjet-printed vias on 0.8-mm-thick substrate have a resistance of ~0.2. An equivalent circuit model of the inkjet-printed stepped vias is also discussed. An inkjet-printed microstrip-to-SIW interconnect and an SIW cavity resonator utilizing the proposed inkjet-printed via fabrication process are also presented. The design of the components and the fabrication steps are discussed, and the measured performances over the microwave frequency range of the prototypes are presented.