Analysis of Frequency-Dependent Permittivity in PolyimideUsing Debye and Cole–Cole Models

In this work, the dielectric properties of polyimide were quantitatively evaluated through analytical modeling using the Debye and Cole–Cole frameworks. Frequency-dependent permittivity behavior was characterized, targeting applications in aerospace polymer dielectrics where high-frequency transparency and communication stability are critical. Experimental measurements yielded a static permittivity of 3.21 and a high-frequency limit of 3.18. The Debye model accurately reproduced the observed frequency-dependent decline, with a maximum absolute deviation of 0.013. In contrast, the Cole–Cole model, despite incorporating distribution parameters for relaxation time, failed to reflect the measured trend, instead producing an unrealistically flat response across the frequency band. These findings indicate that the polarization recovery of polyimide—dominated by dipolar reorientation—is characterized by a relatively narrow relaxation time distribution. As such, the single-relaxation Debye model offers a more suitable representation for this material under the tested conditions. This study demonstrates the feasibility of parameter extraction and uncertainty analysis based on physical dielectric models, and its outcome is expected to support future standardization and design of polymer-based dielectric components for high-frequency systems.