System and method for evaluating materials using ultra wideband signals

• US 20060106546A1
• Filed: 11/17/2004
• Published: 05/18/2006
• Est. Priority Date: 11/17/2004
• Status: Abandoned Application

• Current Assignee: Time Domain Corporation (Humatics Corporation)
• Original Assignee: Time Domain Corporation (Humatics Corporation)
• Inventors: Fullerton, Larry W., Roberts, Mark, Richards, James
• Application Number:
  US10/992,595
• Publication Number:
  US 20060106546A1
• Time in Patent Office: Days
• US Class Current: 702/27
• CPC Class Codes: G01N 22/04 Investigating moisture content
• CPC Class Codes: H04B 1/7163 using impulse radio

Abstract

A system for evaluating properties of materials by probing the materials using ultra wideband signals wherein the probing may be by transmission or by reflection of radiated ultra wideband signals. Received signals may be evaluated by determining signal characteristics including reflection coefficient, transmission attenuation, multipath decay profile, and signal scattering coefficient. Received signals are evaluated using deconvolution and Fourier processing. Test chamber characteristics and boundary reflections may be removed to yield bulk material properties. The system may be calibrated by employing empirical signal measurements from materials with known properties measured by reference techniques.

Claims

1. A method for evaluating a property of a material comprising

directing a first UWB signal toward the material;

receiving a second UWB signal from the material;

determining a received signal characteristic;

relating the received signal characteristic to the material property;

determining the material property.

2. The method of claim 1 wherein said second signal includes a direct transmission signal component.

3. The method of claim 1 wherein said second signal includes a reflected signal component.

4. The method of claim 1 further including a timing source to provide timing for directing a first UWB signal and for receiving a second UWB signal, wherein said receiving a second UWB signal is synchronized to said timing source.

5. The method of claim 1 wherein said determining step includes producing a scan of a plurality of said received signals at a plurality of time offsets.

6. The method of claim 5 wherein the determining step includes deconvolution of a said scan using a received pulse pattern to determine a path impulse transfer function.

7. The method of claim 6 wherein the deconvolution is performed using a CLEAN algorithm.

8. The method of claim 5 wherein the determining step includes a Fourier transform of said scan.

9. The method of claim 5 wherein the determining step includes determining a multipath profile.

10. The method of claim 9 wherein the multipath profile is used to determine an attenuation coefficient.

11. The method of claim 9 wherein the multipath profile is used to determine a scattering coefficient.

12. The method of claim 11 wherein the determination of the scattering coefficient includes subtracting a direct path component.

13. The method of claim 1 wherein the material property is determined by table lookup.

14. The method of claim 1 wherein the material property is determined by an empirically derived equation.

15. The method of claim 1 wherein the material property is one of the group moisture content, density, thickness, conductivity, purity, and salt content.

16. A system for evaluating a property of a material comprising:

a UWB transmitter for generating a probing signal;

a first coupling device for coupling said probing signal to said material;

a UWB receiver for receiving a response signal from said material;

a second coupling device for coupling said response signal from said material to said receiver;

a signal processor for determining a received signal characteristic and relating said received signal characteristic to said property of said material to determine said property of said material.

17. The system of claim 16 wherein the first coupling device is an antenna.

18. The system of claim 16 wherein the first coupling device is a waveguide.

19. The system of claim 16 further including a timing generator coupled to said transmitter and said receiver, wherein said transmitter and said receiver are synchronized.

20. The system of claim 16 wherein the receiver acquires and tracks said response signal.