D Band Dk/Df Measurement With A Fabry-Pérot Open Resonator

Explore the dielectric properties of materials used in millimeter-wave technologies, such as those for 6G applications. Materials like polymers, PCB substrates, and single-crystal wafers are often used, and their microwave properties, particularly dielectric constant (Dk) and loss tangent (Df), need to be measured accurately. The Fabry-Pérot Open Resonator (FPOR) provides a precise technique for measuring these properties in the D band (110-170 GHz), offering a resolution of 1.5 GHz.

The measurement process requires an R&S®ZNA26 vector network analyzer, millimeter-wave converters, and the FPOR fixture. The material under test (MUT) is placed inside the resonator, and the resonance frequency shift and Q factor changes due to the MUT are used to calculate Dk and Df. The system is non-destructive, with no special preparation needed for the MUT.

The FPOR system allows for the measurement of in-plane anisotropy, which other methods cannot detect. This is essential when working with materials that may exhibit this anisotropy due to their physical structure or processing. The accuracy of the Dk measurement is 0.25%, and Df uncertainty is typically better than ±5%, even for materials with very low losses. This method ensures that the characterization of materials is highly accurate, making it ideal for use in high-frequency applications like 6G technology and other advanced millimeter-wave systems.