Relay module for implant

1. A system comprising a wirelessly powered relay device, wherein the wirelessly powered relay device comprising:

a receiver antenna layer configured to receive a first radio-frequency (RF) signal transmitted by a first antenna of a control device, wherein the first RF signal contains electrical energy;

at least one dielectric insulating layer; and

a transmitter antenna layer separated from the receiver antenna layer by the dielectric insulating layer, wherein the transmitter antenna layer is configured to transmit a second RF signal, and the second RF signal is generated using the electrical energy contained in the first RF signal.

2. The system of claim 1 , wherein the receiver antenna layer of the wirelessly powered relay device further comprises one of: a patch antenna, or a dipole antenna, wherein the transmitter antenna layer of the wirelessly powered relay device further comprises one of: a patch antenna, or a dipole antenna.

3. The system of claim 1 , wherein the wirelessly powered relay device further comprises a flexible circuit, wherein the flexible circuit comprises a rectifier and a capacitor, and wherein the capacitor is coupled to the rectifier and configured to store a charge during an initial portion of the first RF signal.

4. The system of claim 3 , wherein the flexible circuit further comprises a counter configured to cause the flexible circuit to generate a trigger upon an end of the initial portion.

5. The system of claim 4 , wherein the flexible circuit further comprises an oscillator, coupled to the counter and configured to generate, upon the trigger, a carrier signal, and wherein the flexible circuit modulates the carrier signal with a stimulus waveform encoded in the first RF signal to generate the second RF signal.

6. The system of claim 5 , wherein the flexible circuit is configured to generate the second RF signal based on the stimulus waveform during a stimulation portion of the first RF signal, wherein the second RF signal has a corresponding carrier frequency that is substantially identical to that of the first RF signal.

7. The system of claim 5 , wherein the flexible circuit further comprises a power amplifier configured to amplify the second RF signal solely using charges accumulated in the capacitor during the initial portion of the first RF signal, and wherein the transmitter antenna layer is configured to transmit the amplified second RF signal via non-inductive coupling to a second antenna on an implantable stimulator device.

8. The system of claim 7 , wherein the power amplifier is configurable to be powered by the charge stored in the capacitor during the initial portion of the first RF signal.

9. The system of claim 5 , wherein the oscillator is configurable to be triggered by an amplitude shift keying in the first RF signal.

10. The system of claim 1 , wherein the receiver antenna layer comprises at least one quarter wavelength antenna, wherein the transmitter antenna layer comprises at least one quarter wavelength antenna.

11. The system of claim 1 , wherein the wirelessly powered relay device is configured to generate the second RF signal during a stimulation portion of the first RF signal and by using a charge accumulated on the wirelessly powered relay device during an initial portion of the first RF signal, wherein the initial portion precedes the stimulation portion, and wherein the second RF signal encodes a stimulus waveform.

12. The system of claim 1 , wherein the wirelessly powered relay device is sized and shaped to be placed outside a subject receiving an implantable stimulator device.

13. The system of claim 12 , further comprising:

an implantable stimulator device comprising a second antenna and at least one electrode, wherein the implantable stimulator device is configured to receive the second RF signal using the second antenna, extract a stimulus waveform from the received second RF signal, and apply the stimulus waveform to a neural tissue of the subject using the at least one electrode.

14. The system of claim 1 , further comprising:

a control device comprising the first antenna, wherein the control device is configured to generate the RF signal and transmit the first RF signal using the first antenna.

15. The system of claim 14 , wherein the control device further comprises a programming interface to allow a user to adjust parameters of a stimulus waveform.

16. The system of claim 14 , wherein the first antenna of the control device comprises one of: a dipole antenna, folded dipole antenna, microstrip antenna, or a phased array of antennas.

17. The system of claim 14 , wherein the control device is configured to transmit the first RF signal at a first carrier frequency, and wherein the wirelessly powered relay device is configured to transmit the second RF signal at a second carrier frequency, and wherein both the first carrier frequency and the second carrier frequency are within a range of about 800 MHz to about 6 GHz.

18. The system of claim 17 , wherein the first carrier frequency and the second carrier frequency are configurable to differ from each other.

19. A system, comprising:

a control module comprising a first antenna, the control module configured to generate a first radio frequency (RF) signal and transmit the first RF signal using the first antenna,

an implantable lead module comprising a second antenna and at least one electrode, the at least one electrode being configured to stimulate an excitable tissue of a subject; and

a relay module configured to:

receive the first RF signal;

generate a second RF signal based on the first RF signal, the second RF signal encoding a stimulus waveform to be applied by the at least one electrode of the implantable lead module to stimulate the excitable tissue of the subject; and

transmit the second RF signal,

wherein the relay module comprises:

a receive antenna layer configured to receive the first RF signal transmitted by the first antenna of the control module;

at least one dielectric insulation layer; and

a transmit antenna layer separated from the receive antenna layer by the dielectric insulating layer, the transmit antenna layer being configured to transmit the second RF signal to the second antenna of the implantable lead module, the second RF signal being generated based on the first RF signal, and the second RF signal encoding a stimulus waveform being applied by the at least one electrode of the implantable lead module to stimulate the excitable tissue of the subject,

wherein the implantable lead module is configured to receive the second RF signal using the second antenna, generate the stimulus waveform from the received second RF signal, and apply the stimulus waveform to the excitable tissue of the subject.

20. The system of claim 19 , wherein the control module further comprises: a programming interface to allow a user to adjust parameters of the stimulus waveform.