Patent ID: 8358141

Claim:
A method for using a scanning evanescent microwave probe to determine electrical properties of a sample, said probe having a tip extending from a coaxial or transmission line resonator, comprising: measuring variation in resonant frequency and quality factor of said resonator resulting from interaction of said tip and said sample; wherein said tip-sample interaction appears as equivalent complex tip-sample capacitance; and wherein said effective complex tip-sample capacitance, C tip-sample is determined according to C tip-sample =C r +C i , wherein C r and C i are the real and imaginary components of the tip-sample capacitance, respectively, Δ ⁢ ⁢ f f 0 = - Cr 2 ⁢ ⁢ C , Δ ⁢ ⁢ ( 1 Q ) = - ( 1 Q + 2 ⁢ C i C r ) ⁢ Δ ⁢ ⁢ f f 0 , Δ ⁢ ⁢ f = f r - f 0 , Δ ⁢ ⁢ ( 1 Q ) = 1 Q - 1 Q 0 , and f 0 and Q 0 are the unloaded resonant frequency and quality factor, respectively.