CAPACITIVE FRINGING FIELD SENSORS AND ELECTRICAL CONDUCTIVITY SENSORS INTEGRATED INTO PRINTED CIRCUIT BOARDS

• US 20150338363A1
• Filed: 05/13/2015
• Published: 11/26/2015
• Est. Priority Date: 05/13/2014
• Status: Abandoned Application

• Current Assignee: Auburn University
• Original Assignee: Auburn University
• Inventors: DEAN, Robert Neal Jr., GUERTAL, Elizabeth Ann, BAGINSKI, Michael Edward
• Application Number:
  US14/711,437
• Publication Number:
  US 20150338363A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B64D 15/20 Means for detecting icing or initiating de-icing
• CPC Class Codes: G01N 27/02 by investigating impedance
• CPC Class Codes: G01N 27/221 by investigating the dielectric properties using microwaves G01N22/00; measuring loss factors or dielectric constants per se G01R27/26
• CPC Class Codes: G01N 33/24 Earth materials G01N33/42 takes precedence
• CPC Class Codes: G01W 1/00 Meteorology

Abstract

A device is provided for sensing the chemical composition of soils and aqueous solutions. The device includes a capacitive fringing field interdigitated electrode sensor integrated into the printed circuit board and configured to sense an electrical impedance. The device also includes an electrical conductivity sensor integrated into the printed circuit board and configured to sense an electrical conductivity. The sensed electrical impedance and electrical conductivity are indicative of chemical properties. The capacitive fringing field interdigitated electrode sensor may also be used to detect the accumulation of ice.

Claims

1. A device, comprising:

a capacitive fringing field interdigitated electrode sensor integrated into a printed circuit board and configured to sense an electrical impedance of soil; and

an electrical conductivity sensor integrated into the printed circuit board and configured to sense an electrical conductivity of surrounding soil, wherein the sensed electrical impedance and the sensed electrical conductivity are indicative of chemical properties of the soil.

4. The device of claim 1, further comprising a soldermask covering the fringing field interdigitated electrode sensor.

5. The device of claim 1, wherein the electrical conductivity sensor is exposed.

6. The device of claim 1, wherein the electrical conducvitty sensor has a surface finish.

7. The device of claim 1, wherein the chemical properties include at least one of water content, salt content, nitrate content, and nitrate-nitrogen content.

8. The device of claim 1, wherein the salt content includes at least one of NaNO₃, KCl, and NaCl.

2. The device, further comprising a temperature sensor integrated into the printed circuit board and configured to sense an environmental temperature.

3. The device of claim 2, wherein the sensed electrical impedance and the sensed electrical conductivity are calibrated with the sensed temperature.

9. A device, comprising:

a capacitive fringing field interdigitated electrode sensor integrated into a printed circuit board and configured to sense an electrical impedance of an aqueous solution; and

an electrical conductivity sensor integrated into the printed circuit board and configured to sense an electrical conductivity of surrounding soil, wherein the sensed electrical impedance and the sensed electrical conductivity are indicative of chemical properties of the aqueous solution.

10. The device of claim 9, wherein the chemical properties include at least one of salt content, nitrate content and nitrite-nitrogen content of the aqueous solution.

11. The device of claim 10, wherein the salt content includes at least one of KCl, NaCl and NaNO₃.

12. A device, comprising:

a printed circuit board; and

a capacitive fringing field interdigitated electrode sensor integrated into the printed circuit board and configured to sense electrical impedance, wherein an abrupt decrease in the sensed electrical impedance is indicative of an accumulation of ice.

13. The device of claim 12, wherein the printed circuit board is rigid or semi-rigid.

14. The device of claim 12, wherein the printed circuit board is flexible allowing the device to be conformally attached or adhered to planar or non-planar surfaces for the detecting the accumulation of ice.

15. The device of claim 12, wherein the device is adapted to detect accumulation of ice associated with plants.

16. The device of claim 12, wherein the device is adapted to detect accumulation of ice associated with aircraft structures.

17. The device of claim 12, where the device is adapted to detect the accumulation of ice associated with spacecraft structures.

18. The device of claim 12, wherein the device is adapted for detecting the accumulation of ice associated with at least one of manmade surface structures, vehicles, buildings, towers, and antennas.

19. The device of claim 12, wherein the device is adapted for detecting the aaccumulation of ice on or in temperature lowering equipment.

20. The device of claim 12, wherein the device is integrated into an RFID tag for remote sensing applications.