The permittivity of the dimethylsulfoxide (DMSO)-water (H₂O) mixture solution was measured by a resonant cavity perturbation method at 2.45 GHz. The measured-results show a specific phenomenon that the imaginary part of the mixture solution permittivity is larger than that of each of the components. The theoretical calculation indicates that the reason for that phenomenon is that high frequency friction is increased due to the mixture of DMSO and H₂O, which implies that the classic mixture formula needs to be modified for calculation of the specific phenomenon.

Key words: mixture solution, effective permittivity, specific phenomenon, mixture formula, hydrogen bond