High-frequency characterization of Limoges porcelain for advanced electronic applications

This paper investigates the potential of Limoges porcelain as a substrate for advanced high-frequency electronic applications through a comprehensive dielectric characterization from 10 kHz to 20 GHz. Preliminary impedance spectroscopy (10 kHz – 1 MHz) reveals a stable relative permittivity (ε r ) between 6.3 and 6.6 for both glazed and unglazed samples, with a slight negative dispersion attributed to interfacial polarization mechanisms. Characterization at microwave frequencies using a cylindrical cavity perturbation method at 4.5 GHz demonstrates a decrease in ε r to values of 5.2 and 5.3 for glazed and unglazed plates, respectively, with a loss tangent (tanδ) of approximately 1.2 × 10 -2 . To assess the performance of the porcelain substrates in integrated configurations, Ti/Cu coplanar waveguide (CPW) resonators were fabricated using standard photolithography and lift-off processes. Broadband electromagnetic modeling up to 20 GHz using Momentum software yields results that are consistent with the experimental resonance frequencies for ε r values between 5.2 and 5.7. While the extraction of intrinsic losses at these frequencies is challenged by a strong interplay between metallic conductivity and dielectric dissipation, the results confirm that Limoges porcelain maintains stable dielectric properties well into the Ku-band. These results support the relevance of porcelain as a chemically and thermally stable substrate, offering robust dielectric performance for RF and microwave packaging applications. • Wideband dielectric characterization of Limoges porcelain (10 kHz–20 GHz) • Stable permittivity from 6.5 to ~5.3 from kHz to microwave frequencies • Limited influence of glazing on dielectric response at GHz frequencies • CPW resonators validate ε r ≈ 5.2 - 5.7 in X- and Ku-bands