Fully 3D printed high performance band-stop filters enabled by three-dimensional design

Additive manufacturing enables the production of high performance radio frequency device components, but most printable materials are plagued by large losses that render them impractical for robust performance applications beyond rapid prototyping. Here, we demonstrate a set of fully three-dimensional (3D) printed band-stop filters fabricated by printing reactive silver ink onto three different additively manufactured resin substrates with varying dielectric properties. Each of the dielectric substrates were fabricated using stereolithography or digital light processing printing methods. By switching from a dielectric with tan delta = 0.06 to one with tan delta = 0.0073, we can decrease the total loss present in the structure by up to 2 dB. As enabled by 3D additive manufacturing, we also show that regardless of the dielectric material, moving from two-dimensional planar patterns to fully-3D topographies allows us to simultaneously widen the filter stopband by 2 GHz and theoretically increase signal rejection by up to 30 dB. This demonstration of a fully additively-manufactured, 3D band-stop filter that closely matches simulations represents a new class of device construction that was previously inaccessible using only 2- and 2.5-D manufacturing techniques.