Sensor assembly, method, and device for monitoring shear force and pressure on a structure
View Patent ↗Shear force and pressure on a structure are simultaneously monitored using signals received from antennas on the structure. The shear force on the structure is monitored using a signal received from a patch antenna on the structure, and the pressure on the structure is monitored using a signal received from a loop antenna on the structure.
1. A sensor system, comprising:
an antenna sensor assembly, comprising:
a shear antenna sensor, comprising;
a first dielectric substrate, the first dielectric substrate comprising a first side and a second side, the first side and the second side opposing one another,
a ground plane having a slot, wherein the ground plane is disposed on the first side of the first dielectric substrate, wherein the slot extends in a first direction; and
a patch antenna disposed on the second side of the first dielectric substrate, wherein lateral deformation of the first dielectric substrate in response to a shear force applied on the ground plane in the first direction shifts a position of the patch antenna and thereby changes an overlap length between the patch antenna and the slot, wherein a patch antenna resonant frequency is based on the overlap length; and
a pressure detection antenna sensor, comprising:
a second dielectric substrate, the second dielectric substrate comprising a third side and a fourth side, the third side and the fourth side opposing one another, the second side being adjacent the third side;
a loop antenna disposed on the fourth side of the second dielectric substrate, and
a reflector disposed on the third side of the second dielectric substrate, wherein vertical deformation of the second dielectric substrate in response to a pressure force applied on the ground plane changes a distance between the loop antenna and the reflector, wherein a loop antenna resonant frequency is based on the distance.
2. The sensor system of claim 1 , wherein the patch antenna is the reflector.
3. The sensor system of claim 1 , wherein the slot is a first slot and the ground plane comprises a second slot.
4. The sensor system of claim 3 , wherein the second slot extends in a second direction that is perpendicular to the first direction.
5. The sensor system of claim 4 , wherein the overlap length is a first overlap length and the patch antenna resonant frequency is a first patch antenna resonant frequency; and
wherein lateral deformation of the first dielectric substrate in response to a shear force applied on the ground plane in the second direction shifts a position of the patch antenna and thereby changes a second overlap length between the patch antenna and the second slot, wherein a second patch antenna resonant frequency is based on the second overlap length.
6. The sensor system of claim 1 , further comprising a receive-transmit antenna and a switch, wherein the antenna sensor assembly is connected to the receive-transmit antenna through the switch.
7. The sensor assembly of claim 6 , further comprising an oscillator configured to control the switch.
8. The sensor assembly of claim 7 , wherein the antenna sensor assembly is a first antenna sensor assembly, the switch is a first switch, and the oscillator is a first oscillator, the sensor assembly further comprising:
a second antenna sensor assembly;
a second switch, wherein the second antenna sensor assembly is connected to the receive-transmit antenna through the switch; and
a second oscillator configured to control the second switch, wherein the second oscillator is configured to control the second switch based on a second frequency and the first oscillator is configured to control the first switch based on a first frequency.
9. The sensor assembly of claim 1 , wherein the shear antenna sensor is stacked on the pressure antenna sensor.
10. A method, comprising:
transmitting one or more interrogation signals to an antenna sensor assembly on a structure, the antenna sensor assembly, comprising:
a shear antenna sensor, compromising:
a first dielectric substrate, the first dielectric substrate comprising a first side and a second side, the first side and the second side opposing one another;
a ground plane having a slot, wherein the ground plane is disposed on the first side of the first dielectric substrate, wherein the slot extends in a first direction;
a patch antenna disposed on the second side of the first dielectric substrate, wherein a lateral deformation of the first dielectric substrate in response to a shear force applied to the ground plane in the first direction shifts a position of the patch antenna and thereby changes an overlap length between the patch antenna and the slot, wherein a patch antenna resonant frequency is based on the overlap length; and
a pressure detection antenna sensor, comprising:
a second dielectric substrate, the second dielectric substrate comprising a third side and a fourth side, the third side and the fourth side opposing one another, the second side being adjacent the third side;
a loop antenna disposed on the fourth side of the second dielectric substrate;
a reflector disposed on the third side of the second dielectric substrate, wherein vertical deformation of the second dielectric substrate in response to an applied pressure force changes a distance between the loop antenna and the reflector, wherein a loop antenna resonant frequency is based on the distance;
wherein the one or more interrogation signals include a first known frequency associated with the patch antenna;
wherein the one or more interrogation signals include a second known frequency associated with the loop antenna
receiving one or more reflection signals from the antenna sensor assembly;
determining the patch antenna resonant frequency based on the one or more reflection signals;
determining the loop antenna resonant frequency based on the one or more reflection signals;
determining a shear force applied on the structure in the first direction based on the patch antenna resonant frequency; and
determining a pressure applied on the structure based on the loop antenna resonant frequency.
11. The method of claim 10 , further comprising:
determining a lateral deformation of the first dielectric substrate based on:
a first frequency shift between the patch antenna resonant frequency and the first known frequency; and
a first calibration curve.
12. The method of claim 11 , further comprising:
determining the shear force based on the lateral deformation and a material property of the first substrate.
13. The method of claim 10 , further comprising:
determining the pressure based on:
a second frequency shift between the loop antenna resonant frequency and the second known frequency; and
a second calibration curve.
14. The method of claim 10 , further comprising:
determining a vertical deformation of the second dielectric substrate based on:
a second frequency shift between the loop antenna resonant frequency and the second known frequency; and
a second calibration curve.
15. The method of claim 10 , wherein the structure is a shoe and the antenna sensor assembly is arranged in a bottom of the shoe and above an insole of the shoe.
16. The method of claim 10 , wherein the slot is a first slot and the ground plane comprises a second slot, wherein the second slot extends in a second direction that is perpendicular to the first direction.
17. The method of claim 16 , wherein the overlap length is a first overlap length and the patch antenna resonant frequency is a first patch antenna resonant frequency; and
wherein lateral deformation of the first dielectric substrate in response to a shear force applied on the ground plane in the second direction shifts the position of the patch antenna and thereby changes a second overlap length between the patch antenna and the second slot, wherein a second patch antenna resonant frequency is based on the second overlap length.
18. The method of claim 10 , further comprising:
a receive-transmit antenna;
a switch, wherein the antenna sensor assembly is connected to the receive-transmit antenna through the switch; and
an oscillator configured to control the switch.
19. The method of claim 18 , wherein the antenna sensor assembly is a first antenna sensor assembly, the switch is a first switch, and the oscillator is a first oscillator, the sensor assembly further comprising:
a second antenna sensor assembly;
a second switch, wherein the second antenna sensor assembly is connected to the receive-transmit antenna through the switch; and
a second oscillator configured to control the second switch, wherein the second oscillator is configured to control the second switch based on a second frequency and the first oscillator is configured to control the first switch based on a first frequency.
20. An antenna sensor assembly, comprising:
a shear antenna sensor, comprising:
a first dielectric substrate, the first dielectric substrate comprising a first side and a second side, the first side and the second side opposing one another,
a ground plane having a slot, wherein the ground plane is disposed on the first side of the first dielectric substrate, wherein the slot extends in a first direction; and
a patch antenna disposed on the second side of the first dielectric substrate, wherein lateral deformation of the first dielectric substrate in response to a shear force applied on the ground plane in the first direction shifts a position of the patch antenna and thereby changes an overlap length between the patch antenna and the slot, wherein a patch antenna resonant frequency is based on the overlap length.