Ultralow RF Signal Loss in Aerosol Jet Printed Silver Microstrip Lines up to 18 GHz

Abstract

Printed radio frequency (RF) electronic components are often prohibitively lossy due to the materials challenges involved in additively manufacturing metals and dielectrics. We use aerosol jet printing of reactive silver inks to fabricate microstrip transmission lines onto commercial RF boards and subsequently extract the insertion loss of the printed silver through bisect de-embedding of the transmission lines. We directly compare the performance of our printed silver microstrips to conventional copper-clad microstrips to benchmark the efficacy of additive manufacturing against traditional processing methods. With an insertion loss nearing that of conventional copper, reactive silver ink printed traces offer dense continuous metals that can reliably act as conductors for RF applications. In addition to the morphological effects on loss from the printed metal itself, we also observe that the effect of substrate surface texture contributes to unexpected loss that may be mitigated by smoothing the surface or aligning the print direction to minimize these effects. Metallizing passive RF components using reactive inks offers a practical approach which will allow RF designers to take advantage of three-dimensional space. This is possible without sacrificing the necessary high conductivity and low loss needed to produce high performance devices for use within aerospace and communications.