An Examination of Aerosol Jet‐Printed Surface Roughness and its Impact on the Performance of High‐Frequency Electronics

Additively manufactured high‐frequency electronics have the potential to feature prominently in the ongoing communications revolution by delivering previously unattainable levels of circuit miniaturization, weight reduction, and conformal and flexible circuitization. However, lack of process optimization has hampered adoption. Specifically, printed conductor surface roughness remains underexplored. Conductor roughness leads to increased loss, which worsens as frequency increases. Despite being studied rigorously with conventional copper conductors, printed roughness is largely ignored. In fact, figures for printed transmission line loss are reported, which exceed simulations because ideal roughness is assumed. Here, process‐induced roughness in aerosol‐jet printed (AJP) transmission lines is analyzed. AJP is used extensively given its resolution, but unique processing artifacts result in roughness profiles dissimilar from conventional copper. Therefore, different existing electromagnetic models are evaluated for simulating printed transmission lines with practical roughness. Subsequently, to demonstrate the influence of roughness on printed electronics, simulations are built to predict the performance of AJP transmission lines and interconnects with varying roughness. Finally, we explore process‐induced surface roughness in AJP in situ UV‐cured dielectrics and silver nanoparticle conductors via the fabrication of AJP transmission lines is explored to minimize AJP roughness with these material types by optimizing platen temperature and in situ UV cure intensity, respectively.