A Resonant Substrate Integrated Waveguide Measurement System for True Relative Permittivity Extraction of PCB Materials up to 90 GHz

This paper presents a resonant measurement method based on substrate integrated waveguide cavities for determination of the true relative permittivity of a PCB material. The sensor is manufactured on the unknown PCB material and in contrast to existing, comparable methods, the extraction process takes into account the metal roughness. The proposed method does not require any reference materials or sensors on different PCB thicknesses. This paper contains considerations regarding the design and simulation as well as measurement results of the sensor system. To validate the measurement system, the extracted relative permittivity values of the RO4350B substrate over the frequency range of 10GHz to 90GHz are presented.