Embedded sensors

1 . An embedded sensor disposed on a textile substrate comprising:

a plurality of transmission traces disposed on the textile substrate;

a plurality of coupling traces disposed on the textile substrate; and

a plurality of fringing field regions formed by adjacent transmission traces and coupling traces, wherein the embedded sensor is configured to operate without a ground plane adjacent to the plurality of transmission traces and the plurality of coupling traces.

2 . The embedded sensor of claim 1 , wherein the plurality of transmission traces each comprise a plurality of plates.

3 . The embedded sensor of claim 1 , wherein the plurality of coupling traces each comprise a plurality of plates.

4 . The embedded sensor of claim 1 , wherein the plurality of transmission traces are positioned orthogonally to the plurality of coupling traces.

5 . The embedded sensor of claim 1 , wherein the fringing field regions form a rectangular array.

6 . The embedded sensor of claim 1 , further comprising a first switch operably coupled to the plurality of transmission traces and a second switch operably coupled to the plurality of coupling traces, wherein the switch is configured to select one of the plurality of coupling traces and one of the plurality of transmission traces.

7 . The embedded sensor of claim 6 , further comprising a processor operably coupled to the first switch and the second switch, and configured to:

select a transmission trace and a coupling traces from the plurality of transmission traces and coupling traces;

measure a capacitance between the transmission trace and the coupling trace.

8 . A method comprising:

transmitting a megahertz-frequency signal through a transmission trace disposed on a textile substrate;

measuring capacitance at a coupling trace, wherein the coupling trace is electrically coupled to the transmission trace and disposed on the textile substrate; and

determining a property of an object based on the capacitance, wherein measuring the capacitance comprises, at a single-channel measurement port selectively coupled to the transmission trace and the coupling trace, obtaining a reflection coefficient S11 and determining the capacitance from a phase of the reflection coefficient.

9 . The method of claim 8 , further comprising transmitting a second signal through a second transmission trace and measuring an electrical coupling value between the transmission trace and the second transmission trace.

10 . The method of claim 8 , further comprising transmitting signals through a plurality of transmission traces and a measuring capacitance at a plurality of coupling traces.

11 . The method of claim 10 , further comprising using a switch to switch between the plurality of transmission traces.

12 . The method of claim 10 , further comprising using a switch to switch between a plurality of coupling traces.

13 . The method of claim 8 , wherein the property of the object is a presence, size, distance, material property or location of the object.

14 . A system comprising:

an embedded sensor disposed on a textile substrate comprising:

a plurality of transmission traces disposed on the textile substrate;

a plurality of coupling traces disposed on the textile substrate; and

a plurality of fringing field regions formed by adjacent transmission traces and coupling traces wherein the embedded sensor is configured to operate without a ground plane adjacent to the plurality of transmission traces and the plurality of coupling traces;

a computing device operably coupled to the embedded sensor, wherein the computing device comprises at least one processor and memory, the memory having computer-executable instructions stored thereon that, when executed by the at least one processor, cause the at least one processor to:

transmit a signal through a transmission trace;

measure a capacitance at a coupling trace, wherein the coupling trace is electrically coupled to the transmission trace;

determine a property of an object based on the capacitance;

and output the property of the object.

15 . The system of claim 14 , wherein the property of the object is a presence, size, distance, material property or location of the object.

16 . The system of claim 14 , further comprising a portable electronic device operably coupled to the computing device, wherein the portable electronic device is configured to: receive the property of the object.

17 . The system of claim 16 , wherein the portable electronic device is configured to display the property of the object on a graphical user interface (GUI).

18 . The system of claim 16 , wherein the portable electronic device is further configured to: output an alarm based on the property of the object.

19 . The system of claim 14 , wherein the embedded sensor further comprises a plurality of transmission traces and a plurality of coupling traces, and a switch operably coupled to the plurality of coupling traces and configured to select a coupling trace from the plurality of coupling traces.

20 . The system of claim 14 , wherein the embedded sensor further comprises a plurality of transmission traces and a plurality of coupling traces, and wherein the computing device is further configured to measure a plurality of capacitances of the plurality of transmission traces and the plurality of coupling traces, and wherein the property of the object is based on the plurality of capacitances.