New methods for the characterization of thin dielectric samples at low frequencies

For many applications the knowledge of the dielectric properties of substrates and covers is absolutely necessary. At higher frequencies or for thicker samples many methods can be used. But, for thin dielectric sheets without metallization the characterization becomes complicate. The new approach presented here makes use of the low capacitance of a very simple set-up. This capacitance is the coupling element between two resonators with slightly different resonance frequencies. These coupled resonators are very sensitive to small changes of the capacitance value which is proportional to the dielectric constant of the investigated material.