Impedance spectrometer with programmable elements

• US 10,690,609 B2
• Filed: 11/25/2019
• Issued: 06/23/2020
• Est. Priority Date: 02/27/2017
• Status: Active Grant

• Current Assignee: William N. Carr
• Original Assignee: William N. Carr
• Inventors: Carr, William N
• Primary Examiner(s): McAndrew, Christopher P
• Application Number:
  US16/693,375
• Publication Number:
  US 20200124553A1
• Time in Patent Office: 211 Days
• Field of Search: 324632
• CPC Class Codes: G01N 2033/245 for agricultural purposes
• CPC Class Codes: G01N 27/021 before and after chemical transformation of the material
• CPC Class Codes: G01N 27/025 a current being generated within the material by induction
• CPC Class Codes: G01N 27/026 Dielectric impedance spectroscopy electrochemical impedance spectroscopy for measuring corrosion G01N17/02
• CPC Class Codes: G01N 33/02 Food
• CPC Class Codes: G01N 33/24 Earth materials G01N33/42 takes precedence
• CPC Class Codes: G01N 33/383 Concrete, cement

Abstract

A system and method for sensing wave impedance of a material using an RF power source with a sensor structure comprised of a resonant electromagnetic radiative filter (MEF). The wave impedance is determined by processing a differential RF signal level within an interrogator comprising an impedance calculator. A differential RF signal between a source signal level and a response signal level affected by field coupling of the REF with a material of interest. In embodiments based on frequency scanning transmissometry (FST), the impedance spectrometer determines both the real and imaginary part of the wave impedance of the material. In embodiments the impedance spectrometer comprises an RFID transponder. In embodiments, the interrogator is disposed as payload on a UAV drone. In embodiments, the impedance spectrometer is a node within a communications network.

Claims

1. An impedance spectrometer for sensing wave impedance of a material, the impedance spectrometer comprising an interrogator, the interrogator comprising a communication/control circuit and an impedance calculator, and a sensing structure, the sensing structure comprising a resonant electromagnetic filter (REF), an RF signal source (T1), and an RF receiver (R1), wherein:

the RF signal source (T1) couples into the material through the REF and is detected by the RF receiver (R1);

an RF response signal from the RF receiver (R1) is affected by the wave impedance of the material;

the transmitter (T1) is operatively-coupled with the interrogator by a wired and/or wireless link;

the receiver (R1) is operatively-coupled with the interrogator by a wired and/or wireless link;

the communications/control circuit provides operational control for the sensing structure and the impedance calculator, and

the impedance calculator determines the real part of the wave impedance of the material based on one or more difference signal databases obtained at a frequency higher than the resonance frequency of the resonant electromagnetic filter (REF).

2. The impedance spectrometer of claim 1 wherein the impedance calculator determines the imaginary part of the wave impedance of the material based on one or more differential signal databases obtained at the at the resonance frequency of the REF.

3. The impedance spectrometer of claim 1 wherein the resonant electromagnetic filter (REF) comprises a metamaterial resonant electromagnetic filter (MREF), the MREF comprising one or more of a split ring resonator (SRR), complementary split ring resonator (CSRR), coupled spiral resonator, fractile resonator and variations/combinations thereof.

4. The impedance spectrometer of claim 1 wherein portions of the interrogator and sensing structure are disposed at one or more physical locations connected through wired and/or wireless means.

5. The impedance spectrometer of claim 1 wherein the sensing structure comprises a passive RFID sensing structure.

6. The impedance spectrometer of claim 5 wherein a wired range extender comprises operative coupling between the receiver (R1) and the interrogator.

7. The impedance spectrometer of claim 1 wherein the sensing structure comprises a strip waveguide, the strip waveguide providing signal coupling between the transmitter (T1) and the receiver (R1) and further wherein the strip waveguide is field-coupled with the resonant electromagnetic filter (REF).

8. The impedance spectrometer of claim 7 wherein the strip waveguide comprises an RF communications antenna within the operative couplings between the interrogator and the sensing structure.

9. The impedance spectrometer of claim 1 wherein the operative couplings between the interrogator and the sensing structure comprise wireless links and are operational at the same or different frequency from the RF signal source.

10. The impedance spectrometer of claim 1 wherein the sensor structure is adapted to comprise one or more transceivers, the transceivers programmed for operation as the transmitter (T1) and/or the receiver (R1).

11. The impedance spectrometer of claim 1 comprising a passive RFID sensor structure, the passive RFID sensor structure adapted to comprise a plurality of the receiver (R1) and resonant electromagnetic filter (REF) wherein the operative couplings with the interrogator and transmitter (T1) are wireless links.

12. The impedance spectrometer of claim 1 wherein the sensing structure is adapted to comprise a digital clock, the digital clock enabling operation of the impedance spectrometer at specific, programmed times and time intervals.

13. The impedance spectrometer of claim 1 wherein the transmitter (T1) and the receiver (R1) are operatively-coupled with a mobile phone through a wired databus or wireless link, the mobile phone comprising at least a portion of the interrogator.

14. The impedance spectrometer of claim 1 wherein the receiver (R1) is at least partially powered by an energy harvester, the energy harvester receiving energy from one or more of RF, solar, thermoelectric or piezoelectric energy harvesting sources.

15. The impedance spectrometer of claim 1 wherein the receiver (R1) is disposed proximal to, or within the material.

16. The impedance spectrometer of claim 1 wherein the interrogator is at least partially disposed as payload on an unmanned aerial vehicle (drone) and the sensor structure is disposed in close proximity to or disposed within the material.

17. The spectrometer of claim 1 wherein the material comprises an agricultural product, in raw or processed form, selected from a group comprised of maize, cocoa, coffee, wheat, barley, tea, nuts, peanuts, tree oils, timber, bales of hay, silage and selected plant leaf.

18. The spectrometer of claim 1 wherein the material comprises one or more of beer, wine, rum and industrial chemicals, the material further comprised of at least two components, the at least two components having a different real part of wave impedance.

19. The spectrometer of claim 1 wherein the material comprises setting cement, wherein the wave impedance of the setting cement changes with time as the cement cures.

20. A method for determining a real and/or imaginary component of a wave impedance of a material comprising a plurality of sensing operations based on calculations implemented in an impedance calculator implementing an algorithm or lookup table, a sensing operation comprising:

transmitting an RF source signal at a controlled frequency from an RF transmitter (T1), wherein the RF source signal is field-coupled through a resonant electromagnetic filter (REF) into a material

receiving the RF response signal from the RF transmitter (T1) into an RF receiver (R1);

measuring a difference-signal level Δ

V_s between the RF source signal and the RF response signal, wherein the difference-signal level Δ

V_s is affected by the wave impedance of the material;

creating a plurality of difference signal databases comprising one or more difference signal levels Δ

V_s wherein the first difference signal database is created using a material of known wave impedance and the second difference signal database is created using a material of unknown wave impedance;

a first calculation is performed in the impedance calculator using the first and second difference signal databases, wherein the controlled frequency is higher than the resonant frequency of the resonant electromagnetic filter (REF), and further wherein said first and second difference signal databases are processed with an algorithmic- or lookup-table formula to determine a real component of the wave impedance of the material;

a second calculation is performed in the impedance calculator using the first and second difference signal databases, wherein the controlled frequency is the same as the resonant frequency of the resonant electromagnetic filter (REF), and further wherein said first and second difference signal databases are processed with an algorithmic- or lookup-table formula together with the real component of the wave impedance of the material to determine both the loss tangent δ and

the imaginary component of the wave impedance of the material.