Antenna assembly

1. An antenna assembly, comprising:

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,

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,

wherein the metal layer is a two-leaf structure that includes two leaves each having three vertices, wherein the two leaves adjoin each other at one vertex, and wherein the remaining vertices of each leaf are rounded as fillets, and

wherein the metal layer is operable to create a higher electric field than a metal layer configured as other than the two-leaf structure while maintaining a surface area identical to the two-leaf structure.

2. The antenna assembly of claim 1 , wherein the metal layer is shaped as a rectangle, and wherein a long axis of the rectangle aligns with a direction of the linear polarization of the electromagnetic energy.

3. The antenna assembly of claim 2 , wherein the metal layer includes four rounded fillets.

4. The antenna assembly of claim 1 , wherein the feed port is located at the vertex where the two leaves adjoin each other.

5. The antenna assembly of claim 1 , wherein the antenna assembly is configured such that the antenna assembly can be bent up to 50 degrees while maintaining the reflection ratio of more than 6 dB.

6. The antenna assembly of claim 1 , wherein the antenna assembly is configured to emit transcranially the linearly polarized electromagnetic energy when the antenna assembly is worn as an ear piece.

7. The antenna assembly of claim 1 , wherein the antenna assembly is configured to emit the linearly polarized electromagnetic energy to a receiving antenna implanted up to 6 cm underneath a subject's skin.

8. The antenna assembly of claim 1 , wherein the antenna assembly is configured such that the reflection ratio of at least 6 dB is maintained regardless of a separation between the metal layer and a subject's skin.

9. The antenna assembly of claim 1 , wherein the antenna assembly is configured such that the reflection ratio of at least 6 dB is maintained with an air gap and without gel coupling between the metal layer and the subject's skin.

10. The antenna assembly of claim 1 , wherein the antenna assembly is configured to operate with a quality factor (Q) no more than 9.

11. The antenna assembly of claim 1 , wherein the antenna assembly is configured to operate at a frequency between 800 MHz and 3 GHz.

12. A system, comprising:

a signal generator configured to generate an input signal containing electrical energy and stimulation pulse parameters,

an antenna assembly coupled to the signal generator and configured to receive an input signal from the signal generator and then transmit the same to a receiving dipole antenna of a passive stimulator device implanted underneath the subject's skin such that 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 in transmitting the input signal and a reflection power seen by the antenna assembly resulting from electromagnetic emission of the input signal, the antenna assembly comprising:

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; and

a metal layer less than 200 um in thickness and configured to emit linearly polarized electromagnetic energy via radiative coupling to the receiving dipole antenna such that the passive stimulator device extracts the electrical energy from the input signal and then uses the extracted energy to create stimulation pulses suitable for stimulating tissue; and

a passive neural stimulator device configured to be implanted underneath the subject's skin, the passive neural stimulator device comprising:

a receiving dipole antenna configured to receive the input signal emitted from the antenna assembly; and

circuitry coupled to the receiving dipole antenna, the circuitry being configured to:

extract electric energy contained in the input signal; and

use the extracted electrical energy to create stimulation pulses suitable for stimulating neural tissue, the stimulation pulses being created according to the stimulation pulse parameters.

13. The system of claim 12 , wherein the antenna assembly is configured to emit the linearly polarized electromagnetic energy to the receiving antenna implanted 1-3 cm underneath a subject's skin.

14. The system of claim 12 , wherein the metal layer is shaped as a rectangle, and wherein a long axis of the rectangle aligns with a direction of the linear polarization.

15. The system of claim 14 , wherein the metal layer is a two-leaf structure that includes two leaves each having three vertices, wherein the two leaves adjoins each other at one vertex, and wherein the remaining vertices of each leaf are rounded as fillets.

16. The system of claim 15 , wherein the feed port is located on the adjoining vertex.

17. The system of claim 12 , wherein the antenna assembly is configured such that the antenna assembly can be to be bent up to 50 degrees while maintaining the reflection ratio of more than 6 dB.

18. The antenna assembly of claim 12 , wherein the antenna assembly is configured such that the reflection ratio of at least 6 dB is maintained with an air gap and without gel coupling between the metal layer and the subject's skin.