Conductivity effects on printed RF interconnects due to printed dielectric ramps

In this work we build upon a previously published technique for printing dielectric ramps and printed RF interconnects across leveled surfaces to gain a better understanding of the effects that the dielectric material itself has on the conductivity of the printed conductive ink. The use of printed dielectric ramps, referred to as fillets, to assist in additively manufactured RF circuits and interconnects can be found throughout literature. One of the most widely used materials for these ramps, the UV-curable adhesive NEA-121, was found to exhibit physical changes when exposed to high curing temperatures and to have a significant effect on the conductivity of a wide variety of commercially available conductive ink materials; in some cases causing a 2x drop in conductivity compared with the expected conductivity reported by the manufacturer. We report on the conductivity effects from printing on the NEA-121 dielectric surface for three commercially available Ag inks for an RF circuit application and report the manufacturing techniques necessary to optimize both the dielectric ramp and the conductive ink performance.