Patent ID: 6891380

Claim:
The method of the invention for measuring characteristics of materials comprising the steps of: providing an oscillating circuit comprising a composite sensor as a combination of at least two sensor components selected from the group consisting of a capacitor and an inductive coil, said at least two sensor components being electrically connected to each other; energizing said oscillating circuit and said composite sensor to cause an inductive-capacitive electromagnetic coupling between said at least two sensor components; generating an inherent resonance in said oscillating circuit and measuring characteristics of said inherent resonance; approaching said composite sensor to said material until a combined sensor-material oscillating circuit occurs due to an inductive-capacitive electromagnetic coupling between said composite sensor and said material, said inductive-capacitive electromagnetic coupling between said composite sensor and said material being generated at a frequency of said inherent resonance that provides a capacitive coupling having a magnitude comparable with an inductive coupling between said sensor and said material; continuing the step of approaching until a system resonance occurs in said aforementioned sensor-material oscillating circuit; measuring characteristics of said system resonance of the combined sensor-material oscillating circuit; comparing said characteristics of said inherent resonance with the characteristics of said system resonance and determining a characteristic difference; and determining the characteristics of said material by matching the characteristic difference with known reference data for the same material; said material being selected from a conductive material and a non-conductive material, wherein said non-conductive material comprises a non-conductive film on a conductive substrate.