Complex Permittivity and Uncertainty Evaluations for an Ultrathin Photosensitive Insulator Film Using a Millimeter Wave Circular Cavity Resonator

An ultrathin dielectric film having thickness under 10 μm and its accurate complex permittivity require for functional and compact 5G / 6G wireless devices. Precise measurement of millimeter wave complex permittivity for the ultrathin film is still quite a challenge. Complex permittivity measurement technique for the ultrathin film based on a resonator method is proposed in millimeter wave frequency band. As a result, complex permittivity of photosensitive films with a thickness of 5 μm to 17 μm is characterized in the frequency range from 30 GHz to 100 GHz. Furthermore, the important points and future tasks for accurate ultrathin film measurements are clarified through the uncertainty analysis.