Isolating and RFID-based sensor from environmental interference
View Patent ↗An RFID-based sensor is provided with an RFID chip and an antenna electrically connected to the RFID chip. The antenna is adapted to receive energy from an RF field and produce a signal. The sensor also includes a sensing material electrically connected to the antenna and having an electrical property which varies in the presence of an environmental factor. The sensor is further provided with a dielectric spacer material and a ground element which is adapted to at least partially isolate the sensing material from the environmental factor.
1. An RFID-based sensor, comprising:
an RFID chip;
an antenna electrically connected to the RFID chip and adapted to receive energy from an RF field and produce a signal;
a sensing material electrically connected or coupled to the antenna and having an electrical property which varies in the presence of an environmental factor;
a dielectric spacer material disposed on the sensing material; and
a ground element or isolator element adapted to at least partially isolate the sensing material from the environmental factor; and
wherein the spacer material comprises a dielectric foam material.
2. The sensor of claim 1 , wherein the sensing material is separated from the ground element.
3. The sensor of claim 2 , wherein the sensing material is separated from the ground element by the spacer material.
4. The sensor of claim 1 , wherein the spacer material is positioned directly adjacent to the ground element.
5. The sensor of claim 1 , wherein the sensing material is positioned directly adjacent to the ground element.
6. The sensor of claim 1 , wherein the spacer material is separated from the ground element.
7. The sensor of claim 1 , wherein the ground element comprises a metallic material.
8. The sensor of claim 1 , wherein the electrical property is the conductivity of the sensing material.
9. The sensor of claim 1 , wherein the electrical property is the dielectric property of the sensing material.
10. The sensor of claim 1 , wherein the electrical property is the magnetic property of the sensing material.
11. The sensor of claim 1 , wherein the electrical property is a combination of one or more of conductivity, complex dielectric constant and complex magnetic permeability.
12. The sensor of claim 1 , wherein the sensing material is positioned beneath the antenna.
13. The sensor of claim 1 , wherein the sensing material is on top of the antenna.
14. The sensor of claim 13 , wherein the sensing material is provided as a coating.
15. The sensor of claim 14 , wherein the coating is provided in discrete areas.
16. The sensor of claim 1 , wherein the ground element has a layer of pressure sensitive adhesive applied thereto.
17. An RFID-based sensor, comprising:
an RFID chip;
an antenna electrically connected to the RFID chip and adapted to receive energy from an RF field and produce a signal;
a sensing material electrically connected or coupled to the antenna and having an electrical property which varies in the presence of an environmental factor;
a dielectric spacer material at least partially incorporated into the sensing material; and
a ground element or isolator element adapted to at least partially isolate the sensing material from the environmental factor; and
wherein the spacer material comprises a dielectric foam material.
18. The sensor of claim 17 , wherein the sensing material and dielectric spacer material are separated from the ground element.
19. The sensor of claim 17 , wherein the sensing material and dielectric spacer material are positioned directly adjacent to the ground element.
20. The sensor of claim 17 , wherein the electrical property includes at least one of conductivity, complex dielectric constant and complex magnetic permeability.