Position sensor and position measurements using millimeter-wave metamaterial

1. A rotation sensor system, comprising:

a rotatable target object configured to rotate about a rotational axis in a rotation direction;

a first millimeter-wave (mm-wave) metamaterial track coupled to the rotatable target object, wherein the first mm-wave metamaterial track is arranged around the rotational axis, and wherein the first mm-wave metamaterial track comprises a first array of elementary structures having at least one first characteristic that changes around a perimeter of the first mm-wave metamaterial track;

at least one transmitter configured to transmit a first electro-magnetic transmit signal towards the first mm-wave metamaterial track, wherein the first mm-wave metamaterial track converts the first electro-magnetic transmit signal into a first electro-magnetic receive signal;

at least one receiver configured to receive the first electro-magnetic receive signal; and

at least one processor configured to determine a rotational position of the rotatable target object based on the received first electro-magnetic receive signal.

2. The rotation sensor system of claim 1 , wherein the at least one first characteristic affects an mm-wave property of the first mm-wave metamaterial track such that the mm-wave property of the first mm-wave metamaterial track changes continuously around the perimeter of the first mm-wave metamaterial track.

3. The rotation sensor system of claim 2 , wherein the at least one first characteristic that changes around the perimeter of the first mm-wave metamaterial track causes at least one coupling effect between elementary structures of the first array of elementary structures to change continuously around the perimeter of the first mm-wave metamaterial track.

4. The rotation sensor system of claim 3 , wherein the at least one coupling effect includes at least one of capacitive near field coupling, inductive near field coupling, waveguide coupling, or far field coupling.

5. The rotation sensor system of claim 1 , wherein the first array of elementary structures has a 360°/N periodical pattern that changes continuously around the perimeter of the first mm-wave metamaterial track, where N is an integer.

6. The rotation sensor system of claim 1 , wherein the rotational position of the rotatable target object is an absolute angular value of the rotatable target object about the rotational axis, the absolute angular value being an angle of rotation about the rotational axis in the range of 0° to 360°.

7. The rotation sensor system of claim 1 , wherein the first mm-wave metamaterial track is configured to convert the first electro-magnetic transmit signal into the first receive signal by at least one of partial reflection or partial absorption, and the first electro-magnetic receive signal is either a partially-reflected signal of the first electro-magnetic transmit signal that is reflected by the first mm-wave metamaterial track or a partially-transmitted signal of the first electro-magnetic transmit signal that passes through the first mm-wave metamaterial track.

8. The rotation sensor system of claim 1 , wherein:

the receiver is configured to demodulate the received first electro-magnetic receive signal to generate a demodulated signal, and

the at least one processor is configured to evaluate a property of the received first electro-magnetic receive signal using at least one of phase analysis, amplitude analysis, or spectral analysis, and determine the rotational position of the rotatable target object based on the evaluated property.

9. The rotation sensor system of claim 1 , wherein:

the at least one transmitter is configured to transmit a second electro-magnetic transmit signal towards the first mm-wave metamaterial track, wherein the first mm-wave metamaterial track converts the second electro-magnetic transmit signal into a second electro-magnetic receive signal, and wherein the first electro-magnetic transmit signal interacts with the first mm-wave metamaterial track at a first angular position and the second electro-magnetic transmit signal interacts with the first mm-wave metamaterial track at a second angular position, wherein the first angular position and the second angular position are shifted from each other by a predetermined amount, and

the at least one receiver is configured to receive the second electro-magnetic receive signal, and determine the rotational position of the rotatable target object based on the first electro-magnetic receive signal and the second electro-magnetic receive signal.

10. The rotation sensor system of claim 9 , wherein the at least one processor is configured to determine a rotation direction of the rotatable target object based on the received first electro-magnetic receive signal and the received second electro-magnetic receive signal.

11. The rotation sensor system of claim 10 , wherein the first array of elementary structures has a 360°/N periodical pattern that changes continuously around the perimeter of the first mm-wave metamaterial track, where N is an integer, and the first angular position and the second angular position are located 90° apart along the 360°/N periodical pattern such that the first receive signal and the second receive signal have a 90° phase difference.

12. The rotation sensor system of claim 1 , further comprising:

a second mm-wave metamaterial track coupled to the rotatable target object, wherein the second mm-wave metamaterial track is arranged around the rotational axis, and wherein the second mm-wave metamaterial track comprises a second array of elementary structures having at least one second characteristic that changes around a perimeter of the second mm-wave metamaterial track,

wherein the at least one transmitter is configured to transmit the first electro-magnetic transmit signal at the second mm-wave metamaterial track, wherein the second mm-wave metamaterial track converts the first electro-magnetic transmit signal into a second electro-magnetic receive signal,

the at least one receiver is configured to receive the second electro-magnetic receive signal, and

the at least one processor is configured to determine the rotational position of the rotatable target object based on the first electro-magnetic receive signal and the second electro-magnetic receive signal.

13. The rotation sensor system of claim 12 , wherein:

the first mm-wave metamaterial track is configured to modify the first electro-magnetic transmit signal, thereby producing the first electro-magnetic receive signal having a first property unique to a first angular position of the first mm-wave metamaterial track at which the first electro-magnetic transmit signal is incident,

the first mm-wave metamaterial track is configured to modify the second electro-magnetic transmit signal, thereby producing the second electro-magnetic receive signal having a second property unique to a second angular position of the first mm-wave metamaterial track at which the second electro-magnetic transmit signal is incident, and

the at least one processor is configured to evaluate the first property of the received first electro-magnetic receive signal and the second property of the received second electro-magnetic receive signal, and determine the rotational position of the rotatable target object based on the evaluated first property and the evaluated second property.

14. The rotation sensor system of claim 1 , further comprising:

a second mm-wave metamaterial track coupled to the rotatable target object, wherein the second mm-wave metamaterial track is arranged around the rotational axis, and wherein the second mm-wave metamaterial track comprises a second array of elementary structures having at least one second characteristic that changes around a perimeter of the second mm-wave metamaterial track,

wherein the at least one transmitter is configured to transmit a second electro-magnetic transmit signal at the second mm-wave metamaterial track, wherein the second mm-wave metamaterial track converts the second electro-magnetic transmit signal into a second electro-magnetic receive signal,

the at least one receiver is configured to receive the second electro-magnetic receive signal, and

the at least one processor is configured to determine the rotational position of the rotatable target object based on the first electro-magnetic receive signal and the second electro-magnetic receive signal.

15. The rotation sensor system of claim 14 , wherein:

the first mm-wave metamaterial track is configured to modify the first electro-magnetic transmit signal, thereby producing the first electro-magnetic receive signal having a first property unique to a first angular position of the first mm-wave metamaterial track at which the first electro-magnetic transmit signal is incident,

the second mm-wave metamaterial track is configured to modify the second electro-magnetic transmit signal, thereby producing the second electro-magnetic receive signal having a second property unique to a second angular position of the second mm-wave metamaterial track at which the second electro-magnetic transmit signal is incident, and

the at least one processor is configured to evaluate the first property of the received first electro-magnetic receive signal and the second property of the received second electro-magnetic receive signal, and determine the rotational position of the rotatable target object based on the evaluated first property and the evaluated second property.

16. The rotation sensor system of claim 14 , wherein:

the first array of elementary structures has a 360°/N periodical pattern that changes continuously around the perimeter of the first mm-wave metamaterial track, wherein N is an integer,

the second array of elementary structures has the 360°/N periodical pattern that changes continuously around the perimeter of the second mm-wave metamaterial track, and

the 360°/N periodical pattern of the second array of elementary structures is rotated 90° about the rotational axis with respect to the 360°/N periodical pattern of the first array of elementary structures such that the first electro-magnetic receive signal and the second electro-magnetic receive signal have a 90° phase difference.

17. The rotation sensor system of claim 16 , wherein the at least one processor is configured to determine a rotation direction of the rotatable target object based on the received first electro-magnetic receive signal and the received second electro-magnetic receive signal.

18. The rotation sensor system of claim 1 , wherein:

the at least one first characteristic of the first array of elementary structures includes at least one of a configuration or an orientation of elementary structures of the first array of elementary structures,

the configuration includes at least one of a size a shape, a spacing, a density, or a type of the of the elementary structures, and

the orientation includes a rotation of the elementary structures with respect to a polarization of the transmit signal.

19. The rotation sensor system of claim 1 , further comprising:

a shaft coupled to the rotatable target object, the shaft extending along the rotational axis,

wherein the first mm-wave metamaterial track forms a closed loop around the shaft.

20. The rotation sensor system of claim 1 , wherein:

the first mm-wave metamaterial track is configured to modify the first electro-magnetic transmit signal, thereby producing the first electro-magnetic receive signal having a first property unique to a first angular position of the first mm-wave metamaterial track at which the first electro-magnetic transmit signal is incident, and

the at least one processor is configured to evaluate the first property of the received first electro-magnetic receive signal, and determine the rotational position of the rotatable target object based on the evaluated first property.

21. The rotation sensor system of claim 1 , wherein first electro-magnetic transmit signal and the first electro-magnetic receive signal are wireless electro-magnetic signals.

22. The rotation sensor system of claim 1 , wherein the first mm-wave metamaterial track is configured to co-rotate with the rotatable target object as it rotates about the rotational axis.

23. A method of determining a rotational position of a rotatable target object, the method comprising:

transmitting a first electro-magnetic transmit signal towards a first millimeter-wave (mm-wave) metamaterial track coupled to the rotatable target object, wherein the first mm-wave metamaterial track is arranged around a rotational axis about which the rotatable target object rotates;

converting, by the first mm-wave metamaterial track, the first electro-magnetic transmit signal into a first electro-magnetic receive signal;

receiving the first electro-magnetic receive signal; and

evaluating the received first electro-magnetic receive signal; and

determining a rotational position of the rotatable target object based on the evaluated first electro-magnetic receive signal.

24. The method of claim 23 , wherein:

the first electro-magnetic receive signal has a first property depending on an angular position of the rotatable target object,

evaluating the received first electro-magnetic receive signal comprises evaluating the first property of the received first electro-magnetic receive signal, and

determining the rotational position of the rotatable target object comprises determining the rotational position of the rotatable target object based on the evaluated first property.

25. The method of claim 23 , further comprising:

transmitting a second electro-magnetic transmit signal at the first mm-wave metamaterial track;

converting, by the first mm-wave metamaterial track, the second electro-magnetic transmit signal into a second electro-magnetic receive signal;

receiving the second electro-magnetic receive signal;

evaluating the received second electro-magnetic receive signal; and

determining the rotational position of the rotatable target object based on the evaluated first electro-magnetic receive signal and the evaluated second electro-magnetic receive signal.

26. The method of claim 25 , further comprising:

determining a rotation direction of the rotatable target object based on the received first electro-magnetic receive signal and the received electro-magnetic second receive signal, wherein the first electro-magnetic transmit signal interacts with a first angular position of the first mm-wave metamaterial track and the second electro-magnetic transmit signal interacts with a second angular position of the first mm-wave metamaterial track, wherein the first angular position and the second angular position are shifted from each other by a predetermined amount.

27. The method of claim 23 , further comprising:

transmitting the first electro-magnetic transmit signal at a second mm-wave metamaterial track coupled to the rotatable target object, wherein the second mm-wave metamaterial track is arranged around the rotational axis about which the rotatable target object rotates;

converting, by the second mm-wave metamaterial track, the first electro-magnetic transmit signal into a second electro-magnetic receive signal;

receiving the second electro-magnetic receive signal;

evaluating the received second electro-magnetic receive signal; and

determining the rotational position of the rotatable target object based on the evaluated first electro-magnetic receive signal and the evaluated second electro-magnetic receive signal.

28. The method of claim 27 , further comprising:

determining a rotation direction of the rotatable target object based on the received first electro-magnetic receive signal and the received second electro-magnetic receive signal.

29. The method of claim 23 , further comprising:

transmitting a second electro-magnetic transmit signal at a second mm-wave metamaterial track coupled to the rotatable target object, wherein the second mm-wave metamaterial track is arranged around the rotational axis about which the rotatable target object rotates;

converting, by the second mm-wave metamaterial track, the second electro-magnetic transmit signal into a second electro-magnetic receive signal;

receiving the second electro-magnetic receive signal;

evaluating the received second electro-magnetic receive signal; and

determining the rotational position of the rotatable target object based on the first electro-magnetic receive signal and the evaluated second electro-magnetic receive signal.

30. The method of claim 29 , further comprising:

determining a rotation direction of the rotatable target object based on the received first electro-magnetic receive signal and the received second electro-magnetic receive signal.

31. A linear position sensor system, comprising:

a linear movable target object configured to move linearly in a linear moving direction;

a millimeter-wave (mm-wave) metamaterial track coupled to the linear movable target object, wherein the mm-wave metamaterial track extends along the linear moving direction, and wherein the mm-wave metamaterial track comprises an array of elementary structures having at least one first characteristic that changes along the mm-wave metamaterial track in the linear moving direction;

at least one transmitter configured to transmit an electro-magnetic transmit signal towards the mm-wave metamaterial track, wherein the mm-wave metamaterial track converts the electro-magnetic transmit signal into an electro-magnetic receive signal;

at least one receiver configured to receive the electro-magnetic receive signal; and

at least one processor configured to determine a linear position of the linear movable target object based on the received electro-magnetic signal.

32. The linear position sensor system of claim 31 , wherein:

the mm-wave metamaterial track is configured to modify the electro-magnetic transmit signal, thereby producing the electro-magnetic receive signal having a property unique to the linear position of the mm-wave metamaterial track at which

the electro-magnetic transmit signal is incident, and the at least one processor is configured to evaluate the property of the received electro-magnetic receive signal, and determine the linear position of the linear movable target object based on the evaluated property.

33. The linear position sensor system of claim 32 , wherein the mm-wave metamaterial track extends parallel to the linear moving direction, and the at least one first characteristic changes continuously along the mm-wave metamaterial track in parallel to the linear moving direction such that each point of incidence on the mm-wave metamaterial track has a unique value for the at least one first characteristic.

34. The linear position sensor system of claim 31 , wherein:

the linear movable target object is configured to move linearly in the linear moving direction on a fixed path, and

the at least one transmitter and the at least one receiver are movably fixed such that the linear movable target object and the mm-wave metamaterial track move relative to the at least one transmitter and the at least one receiver.

35. The linear position sensor system of claim 34 , wherein the determined linear position is an absolute position of the linear movable target object on the fixed path.