Free‐standing and flexible Polyvinylidene fluoride‐trifluoroethylene (P(VDF‐TrFE))—Copper (II) oxide (CuO) nanocomposite films were synthesized using the solution casting method. CuO nanoparticle weight percentage varied as 0%, 10% and 20% in the P(VDF‐TrFE) matrix. X‐ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy were employed for phase confirmation. The morphological changes with the content of CuO nanofiller in the P(VDF‐TrFE) matrix was examined using Field Emission Scanning Electron Microscope (FESEM). The thermal stability of the free‐standing films were tested by the Differential Scanning Calorimeter (DSC). The dielectric permittivity and loss tangent of the films were measured at 10.156 GHz using a Split Post Dielectric Resonator (SPDR) method. The results were verified with the Cavity perturbation technique at 9.174 GHz and showed a decrease in the dielectric properties with a rise in the weight percentage of CuO up to 20%. The present study demonstrates the comparison of the two techniques and the dielectric tunability in microwave frequencies.