Effective Permittivity Measurement of 3D-Printed Dielectric Crystals

Additive manufacturing offers new possibilities in innovative antennas and microwave components. In order to fully exploit its potential, it is necessary to exploit the capabilities offered by the 3D printing technology fully. 3D-printed structured dielectrics are currently receiving much interest in this respect. However, the characterization of the dielectric properties of such crystal structures is not easy, and assumptions on such properties need to be made often. This paper shows a characterization of additively manufactured structured dielectrics in terms of their permittivity and loss tangent in a simple cubic (SC) and face-centered cubic (FCC) crystal geometry with different fill fractions. Measurement results are compared to values predicted by the Maxwell-Garnett effective media approximation and the effective refractive index extracted from a three-dimensional plane wave expansion method (PWEM) in the long-wavelength limit.