Methods, circuits and systems for obtaining impedance or dielectric measurements of a material under test

Abstract

Certain disclosed methods include: transmitting an excitation signal into the MUT and transmitting a reference signal to a set of magnitude and phase (M/P) detectors; receiving the response signal; separately comparing a magnitude and phase for each of the excitation signal and the reference signal with corresponding detection ranges for a first one of the M/P detectors; separately comparing a magnitude and phase for each of the response signal and the reference signal with corresponding detection ranges for a second one of the M/P detectors; iteratively adjusting the excitation signal until the response signal has both a magnitude and a phase within the corresponding detection ranges for the second M/P detector; and iteratively adjusting the reference signal until the reference signal has both a magnitude and a phase within the corresponding detection ranges for the first and the second M/P detectors.

We claim: 
     
         1 . A method of characterizing a response signal for detecting physical characteristics of a material under test (MUT), the method comprising:
 transmitting an excitation signal into the MUT using a transmitting electrode on a sensor array and transmitting a reference signal to a set of magnitude and phase (M/P) detectors;   receiving the response signal from the MUT via a receiving electrode on the sensor array based on the excitation signal;   separately comparing a magnitude and phase for each of the excitation signal and the reference signal with corresponding detection ranges for a first one of the M/P detectors;   separately comparing a magnitude and phase for each of the response signal and the reference signal with corresponding detection ranges for a second one of the M/P detectors;   iteratively adjusting the excitation signal until the response signal has both a magnitude and phase within the corresponding detection ranges for the second M/P detector; and   iteratively adjusting the reference signal until the reference signal has both a magnitude and a phase within the corresponding detection ranges for both the first and second M/P detectors.   
     
     
         2 . The method of  claim 1 , wherein the first M/P detector provides a reading of the magnitude and phase of the excitation signal and the reference signal, and wherein the second M/P detector provides a reading of the magnitude and phase of the reference signal and the response signal. 
     
     
         3 . The method of  claim 2 , wherein the readings are obtained by a computing device configured to control the iterative adjustment of the excitation signal and the reference signal. 
     
     
         4 . The method of  claim 2 , wherein the reading for each of the excitation signal, the reference signal and the response signal comprises separate magnitude and phase components. 
     
     
         5 . The method of  claim 1 , wherein iteratively adjusting the excitation signal comprises adjusting an amplification and phase of the excitation signal. 
     
     
         6 . The method of  claim 1 , further comprising, after verifying that the excitation signal produces a response signal with a magnitude and phase within the corresponding detection ranges for the second M/P detector:
 analyzing data obtained from both the first and the second M/P detectors using a data model about physical characteristics of the MUT to detect at least one physical characteristic of the MUT, wherein the analyzing comprises correlating impedance or dielectric values from the data obtained from both the first and the second M/P detectors with an impedance-to-physical characteristic correspondence table or a dielectric-to-physical characteristic correspondence table.   
     
     
         7 . The method of  claim 1 , further comprising converting the reference signal, the excitation signal and the response signal from analog format to digital format prior to separately comparing the reference signal, the excitation signal and the response signal with the corresponding detection ranges for the first and second M/P detectors. 
     
     
         8 . The method of  claim 1 , wherein the transmitting electrode comprises a single transmitting electrode. 
     
     
         9 . The method of  claim 8 , wherein:
 a) the receiving electrode comprises a single receiving electrode that surrounds the transmitting electrode, or   b) the receiving electrode comprises a plurality of receiving electrodes, and wherein the method further comprises switching between the plurality of receiving electrodes for the response signal using an electrode switch.   
     
     
         10 . The method of  claim 1 , wherein the excitation signal and the reference signal are both generated by a signal generator with a common control signal, and wherein the excitation signal and the reference signal have a common frequency and a distinct magnitude and/or phase. 
     
     
         11 . A system configured to characterize a response signal for detecting physical characteristics of a material under test (MUT), the system comprising:
 a sensor array for communicating with the MUT;   a set of magnitude and phase (M/P) detectors;   a signal generator coupled with the set of M/P detectors and the sensor array; and   a computing device configured to control processes including:
 initiating: a) transmission of an excitation signal into the MUT with a transmitting electrode on the sensor array and b) transmission of a reference signal to the set of magnitude and phase (M/P) detectors; 
 receiving a response signal from the MUT via a receiving electrode on the sensor array based on the excitation signal; 
 separately comparing a magnitude and phase for each of the excitation signal and the reference signal with corresponding detection ranges for a first one of the M/P detectors; 
 separately comparing a magnitude and phase for each of the response signal and the reference signal with corresponding detection ranges for a second one of the M/P detectors; 
 iteratively adjusting the excitation signal until the response signal has both a magnitude and a phase within the corresponding detection ranges for the second M/P detector; and 
 iteratively adjusting the reference signal until the reference signal has both a magnitude and a phase within the corresponding detection ranges for the first and the second M/P detectors. 
   
     
     
         12 . The system of  claim 11 , wherein the computing device is further configured to:
 compute an electromagnetic property of the MUT based on the measured magnitude and phase for the response signal and the reference signal; and   correlate the electromagnetic property with a physical property of the MUT based on a physical model of the MUT or a laboratory test of the MUT, wherein the electromagnetic property comprises one or more of: impedance, susceptance, permittivity or admittance.   
     
     
         13 . The system of  claim 11 , wherein the first M/P detector provide a reading of the magnitude and phase of the excitation signal and the reference signal, and wherein the second M/P detector provides a reading of the magnitude and phase of the reference signal and the response signal. 
     
     
         14 . The system of  claim 13 , wherein the readings are obtained by the computing device configured to control the iterative adjustment of the excitation signal and the reference signal. 
     
     
         15 . The system of  claim 13 , wherein the reading for each of the excitation signal, the reference signal and the response signal comprises separate magnitude and phase components. 
     
     
         16 . The system of  claim 11 , further comprising, after verifying that the excitation signal produces a response signal with a magnitude and phase within the corresponding detection ranges for the second M/P detector and the reference signal has a magnitude and phase within the corresponding detection ranges for the first and second M/P detectors:
 analyzing data obtained from both the first and the second M/P detectors using a data model about physical characteristics of the MUT to detect at least one physical characteristic of the MUT, wherein the analyzing comprises correlating impedance or dielectric values from the data obtained from both the first and the second M/P detectors with an impedance-to-physical characteristic correspondence table or a dielectric-to-physical characteristic correspondence table.   
     
     
         17 . The system of  claim 11 , further comprising converting the reference signal, the excitation signal and the response signal from analog format to digital format prior to separately comparing the reference signal, the excitation signal and the response signal with the corresponding detection ranges for the first and second M/P detectors. 
     
     
         18 . The system of  claim 11 , wherein the transmitting electrode comprises a single transmitting electrode, wherein the receiving electrode comprises a single receiving electrode that surrounds the transmitting electrode. 
     
     
         19 . The system of  claim 11 , wherein the receiving electrode comprises a plurality of receiving electrodes, and wherein the system further comprises an electrode switch coupled with the computing device, wherein the computing device is configured to switch between the plurality of receiving electrodes for the response signal using the electrode switch. 
     
     
         20 . The system of  claim 11 , wherein the excitation signal and the reference signal are both generated by the signal generator with a common control signal, and wherein the excitation signal and the reference signal have a common frequency and a distinct magnitude and/or phase.