Permittivity of 3D Printed NinjaFlex Filament for use in Conformal Antenna Designs up to 20 GHz

NinjaFlex is a flexible (compliant) 3D printing filament which allows the creation of non-rigid objects. Flexible substrates are valuable for antenna design; from consumer products to avionics to biomedical applications, conformality allows antennas to perform in new locations. Key to the antenna design and simulation process are the material properties of the non-conductive substrate layer. To inform and support the design of microwave antennas at higher frequencies, we present a material preparation and measurement method as well as permittivity results for NinjaFlex filament at various infill densities, at frequencies up to 20 GHz.