Patent ID: 7031862

Claim:
A method of estimating moisture content in a material comprising: directing a first frequency (f 1 ) signal and a second frequency (f 2 ) signal through a material; determining a first absolute phase shift (φ 1 ) of said first frequency signal and a second absolute phase shift (φ 2 ) of said second frequency signal; transforming φ 1 to a first corrected absolute phase shift (φ 1c ) and φ 2 to a second corrected absolute phase shift (φ 2c ) in accordance with an expected relationship between φ 1 and φ 2 , wherein said expected relationship is φ 1 =Kφ2f 1 /f 2 , where K is a constant that takes into account dispersion of the material at the first and second frequencies; and estimating moisture content from φ 1c and φ 2c .