Radio frequency and optical reader scanning array
A reader device includes an array of antenna coils configured to electromagnetically couple with devices implanted beneath or within skin of a human body. An implanted device can include a loop antenna or other means configured to couple with at least one antenna coil of the reader device to receive radio frequency energy from and transmit radio frequency transmissions to the reader device. The antenna coil array is configured to mount to the skin surface to improve the coupling between the implanted device and coils of the array. Further, the reader device is configured to select one or more antenna coils of the array and to operate the selected antenna coil to communicate, via radio frequency transmissions, with and/or provide radio frequency power to the implanted device. An antenna coil of the array can be selected based on a detected amount of coupling with the implanted device.
1. A device comprising:
an array of antenna coils, wherein the array of antenna coils is configured to be mounted proximate a skin surface and to span a specified area of the skin surface;
an array of light emitters, wherein the array of light emitters is configured to be mounted proximate the skin surface and to span the specified area of the skin surface when the antenna array is mounted proximate the skin surface, such that light emitted by each light emitter of the array of light emitters illuminates a respective portion of the specified area of the skin surface; and
a controller operably coupled to the array of antenna coils and to the array of light emitters, wherein the controller comprises a computing device programmed to perform controller operations comprising:
selecting a particular antenna coil of the array of antenna coils, wherein selecting the particular antenna coil of the array of antenna coils comprises: (a) detecting a received signal strength of a radio frequency signal that is transmitted from an implanted device implanted beneath the skin surface and received by each antenna coil of the array of antenna coils, and (b) determining which antenna coil of the array of antenna coils has the greatest received signal strength;
after selecting the particular antenna coil, operating at least one particular light emitter proximate the particular antenna coil to transmit light to a light sensor of the implanted device through a portion of subsurface vasculature, such that the light sensor detects a property of the subsurface vasculature based on the transmitted light; and
operating the particular antenna coil of the array of antenna coils to receive a wireless transmission from the implanted device, wherein the wireless transmission is related to the detected property of the subsurface vasculature.
2. The device of claim 1 , wherein at least one antenna coil of the array of antenna coils has a hexagonal shape.
3. The device of claim 1 , wherein at least one antenna coil of the array of antenna coils has a diameter between 3 millimeters and 3.5 millimeters.
4. The device of claim 1 , wherein the windings of individual antenna coils of the array of antenna coils are separated from each other by at least 0.5 millimeters.
5. The device of claim 1 , wherein the device further comprises a ground plane that is separated from the array of antenna coils by a spacing layer.
6. The device of claim 1 , further comprising a contact layer, wherein the contact layer is configured to be in contact with the skin surface and to be disposed between the skin surface and the array of antenna coils when the array of antenna coils is mounted proximate the skin surface.
7. The device of claim 6 , wherein the contact layer has a relative permittivity that is less than 3.5 and a loss tangent that is less than 0.002.
8. The device of claim 6 , wherein the contact layer has a thickness that is between 0.1 millimeters and 0.4 millimeters.
9. The device of claim 1 , wherein the device comprises a window through the array of antenna coils, and wherein at least one light emitter of the array of light emitters is configured to illuminate a portion of the skin surface though the window.
10. The device of claim 1 , further comprising:
a radio frequency switch, wherein each antenna coil of the array of antenna coils is coupled to the radio frequency switch, wherein the controller is operably coupled to the radio frequency switch, and wherein operating the particular antenna coil of the array of antenna coils comprises operating the radio frequency switch to couple the particular antenna coil to the controller.
11. The device of claim 10 , wherein each antenna coil of the array of antenna coils is coupled to the radio frequency switch via a respective matching circuit.
12. The device of claim 1 , wherein the at least one particular light emitter includes a light emitter disposed at a center of the particular antenna coil.
13. The device of claim 1 , wherein the at least one particular light emitter includes a light emitter that is offset from a center of the particular antenna coil.
14. A method comprising:
mounting a reader device to a skin surface, wherein the reader device comprises an array of antenna coils that spans a specified area of the skin surface and an array of light emitters that spans the specified area of the skin surface, wherein an implanted device is implanted beneath the skin surface;
selecting a particular antenna coil of the array of antenna coils, wherein selecting the particular antenna coil of the array of antenna coils comprises: (a) detecting a received signal strength of a radio frequency signal that is transmitted from an implanted device implanted beneath the skin surface and received by each antenna coil of the array of antenna coils, and (b) determining which antenna coil of the array of antenna coils has the greatest received signal strength;
after selecting the particular antenna coil, operating at least one particular light emitter proximate the particular antenna coil to transmit light to a light sensor of the implanted device through a portion of subsurface vasculature, such that the light sensor detects a property of the subsurface vasculature based on the transmitted light; and
operating the particular antenna coil of the array of antenna coils to receive a wireless transmission from the implanted device, wherein the wireless transmission is related to the detected property of the subsurface vasculature.
15. The method of claim 14 , wherein at least one antenna coil of the array of antenna coils has a diameter between 3 millimeters and 3.5 millimeters.
16. The method of claim 14 , wherein the reader device further comprises a contact layer, wherein the contact layer is configured to be in contact with the skin surface and to be disposed between the skin surface and the array of antenna coils when the array of antenna coils is mounted proximate the skin surface, and wherein the contact layer has a thickness that is between 0.1 millimeters and 0.4 millimeters.
17. The method of claim 14 , wherein the radio frequency signal received by a given antenna coil is transmitted by the implanted device responsive to radio frequency energy transmitted by the given antenna coil.
18. The method of claim 14 , wherein the at least one particular light emitter includes a light emitter disposed at a center of the particular antenna coil.
19. The method of claim 14 , wherein the at least one particular light emitter includes a light emitter that is offset from a center of the particular antenna coil.