A Cost-Effective, Wideband Destructive Technique for Thin-Film Substrate Characterization in RF Circuits

This paper presents a validated, cost-effective technique for the wideband characterization of thin-film substrate materials in RF circuits. The method leverages traditional resonant structures to determine key parameters—relative permittivity and loss tangent—while accounting for fabrication process variability. Covering a broad frequency range (8–16 GHz), the proposed technique can be adapted for other ranges by modifying the resonant structure dimensions. By combining reflection coefficient and input impedance measurements of a Multimode patch antenna, substrate properties are accurately extracted using an iterative numerical fitting process. This approach provides RF designers with precise material data necessary to enhance circuit performance, and is especially useful for thin-film substrates. The technique’s validity is demonstrated through excellent agreement between simulations and measurements, providing a practical, scalable solution for industrial and research applications.