Patent ID: 7534334

Claim:
A filtering device, comprising: a dielectric base portion comprising an open flow channel formed therein, said open flow channel comprising connected channel regions, wherein each of said channel regions comprise a predetermined depth, a uniform rectangular cross section, a longitudinal axis, and first and second side walls each aligned substantially parallel to said longitudinal axis, wherein at least first and second channel regions intersect at a first intersection plane passing through an intersection between said respective first side walls and said respective second side walls of said at least first and second channel regions, and wherein a normal to said first intersection plane is oriented at a first angle, θ 11 , with respect to said longitudinal axis of said first channel region, and oriented at a second angle, θ 12 , with respect to the longitudinal axis of said second channel region; said first channel region further comprising a first predetermined channel depth, d 1 , said first predetermined channel depth providing a means for establishing a first average permeability, σ 1 , in said first channel region, wherein 0.75σ 1 < σ 1 <1.25σ 1 ; and said second channel region further comprising a second predetermined channel depth, d 2 , said second predetermined channel depth providing a means for establishing a second average permeability, σ 2 , in said second channel region, wherein 0.75σ 2 < σ 2 <1.25σ 2 , wherein σ 1 and σ 2 are first and second predetermined design permeabilities, respectively proportional to d 1 and d 2 , and related by a compatibility condition comprising tan ⁢ ⁢ θ 11 σ 1 = tan ⁢ ⁢ θ 12 σ 2 , and wherein a fluid flowing from said first channel region into said second channel region and comprising a flux that is substantially uniform in said first channel region, remains substantially uniform in said second channel region; a first electrode disposed at an inlet of said open flow channel and second electrode disposed at an outlet of said open flow channel, said electrodes attached to an adjustable source of electrical energy; wherein said electrodes and said adjustable source of electrical energy are configured to provide a steady electrical field across each channel region rectangular cross section, wherein said electric field transports a conduction fluid through said open flow channel, and wherein the electric field is further adjustable to impart a dielectrophoretic force to a particle suspended in said conduction fluid sufficient to inhibit said particle from passing said first intersection plane; a collection channel opening into said flow channel and disposed between said inlet and said outlet; and a dielectric cover portion disposed over said base portion.