Permittivity monitor uses ultra wide band transmission
First Claim
1. An apparatus for measuring permittivity of a medium, the apparatus comprising:
- (a) an ultra wide band transmitter for wirelessly transmitting an electromagnetic waveform through said medium;
(b) an ultra wide band receiver for wirelessly receiving a resultant waveform through said medium in response to the transmitter;
(c) a measurement means for measuring amplitude of the resultant waveform as a function of time, the measurement means comprising an implementation of a real-time digitizer using a successive approximation technique;
(d) a synchronization means for synchronizing the measurement means with the transmitter; and
(e) a means of analysis for extracting characteristic features of the resultant waveform to determine the permittivity of said medium.
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Abstract
Narrow pulses transmitted wirelessly from a transmitting antenna to a receiving antenna are used to measure the electrical permittivity of the medium of interest between the two antennas. Timing signals are transmitted along a shielded transmission line coincident with the wireless transmission through the medium. The received waveform is digitized in the time domain and analyzed to determine the propagation time. The effects of dispersion caused by the conductive and dielectric properties of the medium on the transmitted waveform are overcome through analysis of the digitized waveform, resulting in an accurate measurement of the propagation time and thus the permittivity of the medium, from which volumetric moisture content may be derived.
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Citations
23 Claims
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1. An apparatus for measuring permittivity of a medium, the apparatus comprising:
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(a) an ultra wide band transmitter for wirelessly transmitting an electromagnetic waveform through said medium; (b) an ultra wide band receiver for wirelessly receiving a resultant waveform through said medium in response to the transmitter; (c) a measurement means for measuring amplitude of the resultant waveform as a function of time, the measurement means comprising an implementation of a real-time digitizer using a successive approximation technique; (d) a synchronization means for synchronizing the measurement means with the transmitter; and (e) a means of analysis for extracting characteristic features of the resultant waveform to determine the permittivity of said medium. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of determining permittivity of a moisture-bearing medium, comprising the steps of:
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(a) providing a transmitting antenna to wirelessly transmit an ultra wide band electromagnetic waveform into the medium; (b) providing a receiving antenna for wireless reception through the medium of a resultant waveform in response to the wirelessly transmitted waveform; (c) providing a latching comparator connected to said receiving antenna; (d) providing a shielded transmission line connected to said latching comparator; (e) applying the ultra wide band electromagnetic waveform to said transmitting antenna; (f) digitizing portions of the resultant waveform in real-time by successive approximation; and (g) extracting pertinent characteristic features from which the permittivity can be determined. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification