Torque measurement using millimeter-wave metamaterial

A method of determining a torque applied to a rotatable shaft, the method comprising:

• transmitting electro-magnetic transmit signals towards a first mutually coupled structure and a second mutually coupled structure that are mechanically coupled to the rotatable shaft;
• converting, by the first mutually coupled multitrack structure, a first one of the electro-magnetic transmit signals into a first electro-magnetic receive signal;
• converting, by the second mutually coupled multitrack structure, a second one of the electro-magnetic transmit signals into a second electro-magnetic receive signal;
• receiving the first electro-magnetic receive signal and the second electro-magnetic receive signal in a time-multiplexed manner;
• evaluating the received first electro-magnetic receive signal and the received second electro-magnetic receive signal;
• and
• determining the torque applied to the rotatable shaft based on the evaluated first electro-magnetic receive signal and the evaluated second electro-magnetic receive signal.

A torque measurement system, comprising:

• a first rotatable carrier structure mechanically coupled to a rotational shaft and configured to rotate about a rotational axis in a rotation direction;
• a second rotatable carrier structure mechanically coupled to the rotational shaft and configured to rotate about the rotational axis in the rotation direction, wherein the second rotatable carrier structure is spaced apart from the first rotatable carrier structure;
• a first mutually coupled structure comprising a first track mechanically coupled to the first rotatable carrier structure and a second track mechanically coupled to the second rotatable carrier structure, wherein the first track and the second track are coupled together by a first torque dependent coupling;
• a second mutually coupled structure comprising a third track mechanically coupled to the first rotatable carrier structure and a fourth track mechanically coupled to the second rotatable carrier structure, wherein the third track and the fourth track are coupled together by a second torque dependent coupling,
• wherein, in response to a rotation of the rotational shaft, the first torque dependent coupling is configured to increase and the second torque dependent coupling is configured to decrease.