Patent ID: 7190176

Claim:
A sample analysis apparatus that measures an amount of water in a sample comprising: (i) a microwave generator that generates a continuous linearly sweeping microwave signal varying in frequency; (ii) a microwave transmitter that transmits the generated signal; (iii) a microwave receiver that receives the transmitted signal; (iv) at least one microwave analyser that generates an output signal, which is operatively connected to the microwave transmitter and to the microwave receiver; said output signal indicating a phase shift and/or an attenuation of amplitude of the microwave signal when comparing the generated signal and the received signal, and the at least one microwave analyser is capable of measuring the phase shift and/or attenuation of the amplitude of the microwave signal by random stratified sampling of the received signal; (v) means for determining a depth of the sample located between said microwave transmitter and said microwave receiver; and (vi) a processor that determines the amount of the water in the sample from the depth and said output signal using the equation: Moisture content= M 0 +M 1*(Attenuation/Depth of sample)+ M 2*(Velocity/Depth of sample) M 3*(Velocity/Depth of sample) 2 +M 4*(Attenuation/Depth of sample) 2 ; wherein Attenuation=(amplitude measured with sample)−(amplitude measured without sample); Velocity=(microwave velocity measurement with sample)−(microwave velocity measurement without sample); and Depth of sample=(Depth with sample)−(depth without sample); and M 0 , M 1 , M 2 , M 3 and M 4 are calibration coefficients determined by performing a simple linear regression of variables: (Attenuation/Depth of sample), (Velocity/Depth of sample), (Velocity/Depth of sample) 2 and (Attenuation/Depth of sample) 2 against experimentally determined values for water.