Multi-frequency microwave sensor for temperature independent measurement of moisture
First Claim
1. A method of measuring two or more parameters of a composition, which includes water, that comprises the steps of:
- a. directing microwave radiation over a spectrum of wavelengths from an antenna to be incident upon the composition;
b. measuring the microwave radiation over the spectrum of wavelengths that emerges from the composition;
c. determining a reflected and/or transmitted transfer function of the composition over the spectrum of wavelengths;
d. relating the determined transfer function of the composition over the spectrum of wavelengths to two or more parameters of the composition, that include water temperature and at least one of composition percent moisture or composition basis weight, by applying a model, with the proviso that an independent temperature measurement of the composition is not required; and
e. predicting the water temperature and at least one of composition percent moisture or composition basis weight.
1 Assignment
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Accused Products
Abstract
Microwave techniques for measuring moisture and other properties of paper and related products without requiring an independent measurement of temperature are provided. A sensor directly measures the reflection or transmission of microwaves at a number of well-chosen frequencies so as to characterize the absorption spectrum of the product. The technique of measuring the parameters of a composition includes: (a) directing incident microwave radiation over a spectrum of wavelengths from an antenna upon the composition; (b) measuring the microwave radiation over the spectrum of wavelengths that emerges from the composition; (c) determining the reflected and/or transmitted transfer function; and (d) relating the transfer function of the composition to the parameters of the composition by applying a theoretic, calibrated, or hybrid model. The product moisture and temperature are extracted from the transfer function.
22 Citations
20 Claims
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1. A method of measuring two or more parameters of a composition, which includes water, that comprises the steps of:
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a. directing microwave radiation over a spectrum of wavelengths from an antenna to be incident upon the composition; b. measuring the microwave radiation over the spectrum of wavelengths that emerges from the composition; c. determining a reflected and/or transmitted transfer function of the composition over the spectrum of wavelengths; d. relating the determined transfer function of the composition over the spectrum of wavelengths to two or more parameters of the composition, that include water temperature and at least one of composition percent moisture or composition basis weight, by applying a model, with the proviso that an independent temperature measurement of the composition is not required; and e. predicting the water temperature and at least one of composition percent moisture or composition basis weight. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A sensor for measuring at least two properties of a composition, which includes water, that comprises:
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an antenna, which emits microwave radiation over a spectrum of wavelengths at the composition; a receiver operable to detect reflected or transmitted radiation from the composition and to provide electrical detection signals; signal generator that generates first signals to the antenna to cause the antenna to emit microwave radiation at two or more frequencies at the composition and second signals that are indicative of the two or more frequencies; and a processor that receives the electrical detection signals and the second signal and that is operable to determine water temperature and at least one of composition percent moisture or composition basis weight by applying a model with the proviso that an independent temperature measurement of the composition is not required. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification