Patent ID: 7868627

Claim:
A method for measuring dielectric characteristics of materials, comprising: generating an extremely high frequency (EHF) signal, dividing the EHF signal into a reference signal and a probe signal, contacting the material with a rectangular waveguide comprising a prism-shaped dielectric insert, wherein the insert is in contact with the material, irradiating the material with the EHF signal through the waveguide, receiving a reflected signal, a reference signal, and a combined signal, and detecting the reflected signal, the reference signal, and the combined signal, wherein the ratio of the wave number of the EHF signal in dielectric-filled free space to the longitudinal wave number of the EHF signal in the waveguide is (∈·k 2 ) 0.5 /(∈·k 2 −(π/a) 2 ) 0.5 and is between 1 and 1.07, where ∈ is a relative dielectric permittivity of the insert; where a is the smaller dimension of the rectangular cross-section of the waveguide; and where k is a wave number of the EHF signal for empty free space equal to k=2πv/c, where v is the radiation frequency, and c is the speed of light in vacuum.