Low-profile wireless passive resonators for sensing
View Patent ↗A resonator for sensing a physical or an environmental parameter includes a support having a top surface that provides a ground plane, and a polymer-derived ceramic (PDC) element positioned on the top surface including a PDC layer, and a metal patch on the PDC layer. The metal patch is electrically isolated from all surrounding structure, and the resonator has a resonant frequency that changes as a function of the physical or environmental parameter. A system for wirelessly sensing a physical or environmental parameter includes at least one resonator and a wireless RF reader located remotely from the resonator for transmitting a wide-band RF interrogation signal that excites the resonator. The wireless RF reader detects a sensing signal retransmitted by the resonator and includes a processor for determining the physical or environmental parameter at the location of the resonator from the sensing signal.
1. A resonator for sensing a physical or an environmental parameter, comprising:
a support having a top surface that provides a ground plane, and
a polymer-derived ceramic (PDC) element positioned on said top surface including:
a PDC layer having a top PDC surface and a bottom PDC surface, said bottom PDC surface on said top surface, and
a metal patch on said top PDC surface;
wherein said metal patch is electrically isolated from all surrounding structures,
wherein said resonator has a resonant frequency that changes as a function of said physical or said environmental parameter, and
wherein an unloaded quality (Q) factor of said resonator and a radiation Q factor of said resonator are Q-factor matched being within 50% of one another.
2. The resonator of claim 1 , wherein said support is a metal support that provides said top surface.
3. The resonator of claim 1 , wherein said support is a non-metal support, further comprising a metal layer between said support and said PDC element.
4. The resonator of claim 1 , further comprising a dielectric capping layer on said metal patch that prevents oxidation of said metal patch.
5. The resonator of claim 4 , wherein said dielectric capping layer comprises another PDC layer or a layer of Al 2 O 3 .
6. The resonator of claim 1 , wherein said PDC layer includes an air gap (cavity) within, and said resonator provides a pressure sensitive resonant frequency that changes as a height of said air gap changes with pressure to provide a pressure sensor.
7. The resonator of claim 1 , wherein an unloaded quality (Q) factor of said resonator is ≧100.
8. The resonator of claim 1 , wherein a nominal resonant frequency of said resonator is between 1 and 40 GHz.
9. The resonator of claim 1 , wherein said PDC element comprises SiAlCN, SiCN or SiBCN.
10. A system for wirelessly sensing at least one physical or environmental parameter, comprising:
at least one resonator for sensing said physical or said environmental parameter comprising:
a support having a top surface, and
a polymer-derived ceramic (PDC) element positioned on said top surface including:
a PDC layer having a top PDC surface and a bottom PDC surface, said bottom PDC surface on said top surface, and
a metal patch on said top PDC surface,
wherein said metal patch is electrically isolated from all surrounding structure, and
wherein said resonator has a resonant frequency that changes as a function of said physical or said environmental parameter, and wherein an unloaded quality (Q) factor of said resonator and a radiation Q factor of said resonator are Q-factor matched being within 50% of one another, and
a wireless RF reader located remotely from said resonator, said wireless RF reader for transmitting a wide-band RF interrogation signal that excites said resonator, wherein said wireless RF reader detects a sensing signal retransmitted by said resonator and includes a processor for determining said physical or said environmental parameter at a location of said resonator.
11. The system of claim 10 , wherein a nominal resonant frequency of said resonator is between 1 and 40 GHz.
12. The system of claim 10 , wherein said support is a metal support that provides said top surface.
13. The system of claim 10 , wherein said support is a non-metal support, further comprising a metal layer between said support and said PDC element.
14. The system of claim 10 , further comprising a dielectric capping layer on said metal patch that prevents oxidation of said metal patch.
15. The system of claim 10 , wherein said PDC layer includes an air gap (cavity) within, and said resonator provides a pressure sensitive resonant frequency that changes as a height of said air gap changes with pressure to provide a pressure sensor.
16. The system of claim 10 , wherein said PDC element comprises SiAlCN, SiCN or SiBCN.
17. The system of claim 10 , wherein said at least one resonator comprises a plurality of said resonators, said plurality of said resonators bonded to different locations within said system.
18. The system of claim 17 , wherein said plurality of said resonators each provide different resonant frequencies.