Antenna assembly for supplying power to an implantable neural stimulator device
An antenna assembly includes a metal layer configured to emit linearly polarized electromagnetic energy to a receiving antenna implanted underneath a subject's skin; and a feed port configured to connect the antenna assembly to a signal generator such that the antenna assembly receives an input signal from the signal generator and then transmits the input signal to the receiving dipole antenna, wherein the antenna assembly is less than 200 um in thickness, and wherein the metal layer is operable as a dipole antenna with a reflection ratio of at least 6 dB, the reflection ratio corresponding to a ratio of a transmission power of the antenna assembly in transmitting the input signal and a reflection power seen by the antenna assembly resulting from electromagnetic emission of the input signal.
1. A system, comprising:
a signal generator configured to generate an input signal containing electrical energy; and
an antenna assembly, comprising:
a metal layer having a rectangular structure that includes a first axis and a second axis, the first axis being at least 1.5 times longer than the second axis and the metal layer is configured to emit a linearly polarized electric field to a receiving antenna implanted underneath a subject's skin such that the receiving antenna implanted underneath the skin is non-inductively coupled to the antenna assembly; and
a feed port configured to connect the antenna assembly to the signal generator such that the antenna assembly receives the input signal from the signal generator to emit the linearly polarized electric field to the receiving antenna.
2. The system of claim 1 , wherein the antenna assembly operates with a reflection ratio of at least 6 dB, the reflection ratio corresponding to a ratio of a transmission power of the antenna assembly when driven by the input signal and a reflection power seen by the antenna assembly resulting from emission of the linearly polarized electric field to the receiving antenna implanted underneath the skin of the subject.
3. The system of claim 1 , wherein the electric field is linearly polarized along the first axis of the metal layer.
4. The system of claim 3 , wherein the receiving antenna is a dipole antenna and a long axis of the receiving antenna is aligned with the first axis of the metal layer.
5. The system of claim 4 , wherein the receiving antenna also has a short axis and the long axis being at least 0.5 times a length of the first axis and the short axis being at least five times shorter than the second axis.
6. The system of claim 5 , wherein the long axis is shorter than the first axis.
7. The system of claim 5 , wherein the antenna assembly operates with a reflection ratio of at least 6 dB, the reflection ratio corresponding to a ratio of a transmission power of the antenna assembly when driven by the input signal and a reflection power seen by the antenna assembly resulting from emission of the linearly polarized electric field to the receiving antenna implanted underneath the skin of the subject.
8. The system of claim 1 , wherein the antenna assembly is configured such that a reflection coefficient of the feed port at an operating frequency of the antenna assembly remains below −6 dB when the antenna assembly is positioned between 0 to 2 centimeters away from the skin.
9. The system of claim 1 , wherein the receiving antenna is a dipole antenna and the linearly polarized electric field is aligned with a long axis of the receiving antenna.
10. The system of claim 1 , wherein the metal layer is less than 200 μm in thickness.
11. An antenna assembly comprising:
a metal layer having a rectangular structure that includes a first axis and a second axis, the first axis being at least 1.5 times longer than the second axis and the metal layer is configured to emit a linearly polarized electric field to a receiving antenna implanted underneath a subject's skin such that the receiving antenna implanted underneath the skin is non-inductively coupled to the antenna assembly; and
a feed port configured to connect the antenna assembly to a signal generator such that the antenna assembly receives an input signal from the signal generator to emit the linearly polarized electric field to the receiving antenna.
12. The antenna assembly of claim 11 , wherein the antenna assembly operates with a reflection ratio of at least 6 dB, the reflection ratio corresponding to a ratio of a transmission power of the antenna assembly when driven by the input signal and a reflection power seen by the antenna assembly resulting from emission of the linearly polarized electric field to the receiving antenna implanted underneath the skin of the subject.
13. The antenna assembly of claim 11 , wherein the electric field is linearly polarized along the first axis of the metal layer.
14. The antenna assembly of claim 13 , wherein the receiving antenna is a dipole antenna and a long axis of the receiving antenna is aligned with the first axis of the metal layer.
15. The antenna assembly of claim 14 , wherein the receiving antenna also has a short axis and the long axis being at least 0.5 times a length of the first axis and the short axis being at least five times shorter than the second axis.
16. The antenna assembly of claim 15 , wherein the long axis is shorter than the first axis.
17. The antenna assembly of claim 15 , wherein the antenna assembly operates with a reflection ratio of at least 6 dB, the reflection ratio corresponding to a ratio of a transmission power of the antenna assembly when driven by the input signal and a reflection power seen by the antenna assembly resulting from emission of the linearly polarized electric field to the receiving antenna implanted underneath the skin of the subject.
18. The antenna assembly of claim 11 , wherein the antenna assembly is configured such that a reflection coefficient of the feed port at an operating frequency of the antenna assembly remains below −6 dB when the antenna assembly is positioned between 0 to 2 centimeters away from the skin.
19. The antenna assembly of claim 11 , wherein the receiving antenna is a dipole antenna and the linearly polarized electric field is aligned with a long axis of the receiving antenna.
20. The antenna assembly of claim 11 , wherein the metal layer is less than 200 μm in thickness.