Patent ID: 6930492

Claim:
A method using surface microwaves for measuring and determining density or moisture content of a material, comprising the steps of: (a) positioning the material within a proximate free space region spanning immediately above externally exposed flat top surface of a surface microwave waveguide, said surface microwave waveguide is comprised of: (i) an electrically conducting rectangular block including a rectangular channel which is open to free space, said channel is defined by two parallel inner side walls of said block and a third inner bottom wall of said block orthogonally joining said side walls, said channel extends along entire length of said block, top surface of said block is fiat and externally exposed to free space; and (ii) a dielectric rectangular insert element compactly fitting into and along said channel in between said parallel inner side walls of said block and extending along said entire length of said block, each of first end and second end of said insert element is contiguous with corresponding first end and second end of said block, top surface of said insert element is flat, externally exposed to free space, and contiguous with said flat top surface of said block such that said flat top surface of said insert element and said flat top surface of said block form said externally exposed flat top surface of said surface microwave waveguide; (b) transmitting microwaves into first end of said surface microwave waveguide, such that a first portion of said transmitted microwaves propagate within and through said surface microwave waveguide and a second portion of said transmitted microwaves propagate within and through said proximate free space region including the material, such that parameters of said propagating microwaves are perturbed by the material and are a function of density or moisture content of the material within said proximate free space region; and (c) receiving said first portion and said second portion of said propagating microwaves exiting second end of said surface microwave waveguide, for forming received microwaves, said parameters of said transmitted microwaves and of said received microwaves are useable for determining the density or moisture content of the material.