Implantable relay module

1. A passive implantable relay module, comprising:

a first coupler arm arranged along a longitudinal axis of the passive implantable relay module and configured to wirelessly receive electromagnetic energy radiated through non-inductive coupling from a transmitting antenna located outside a subject's body; and

a second coupler arm longitudinally arranged along the long axis of the passive implantable relay module and configured to wirelessly transfer electromagnetic energy through non-inductive coupling to a receiving antenna on a passive wireless neural stimulator device that has been implanted inside the subject such that the passive wireless neural stimulator device is wirelessly powered; and

a connector portion sized and shaped to connect the first coupler arm to the second coupler arm.

2. The passive implantable relay module of claim 1 , wherein the connector portion comprises a first metal core that is sized and shaped to run a longitudinal length that is approximately a half wavelength of electromagnetic waves propagating thereon from the first coupler arm to the second coupler arm and along the longitudinal axis of the passive implantable relay module.

3. The passive implantable relay module of claim 1 , wherein the connector portion comprises a first metal core that is sized and shaped to run a longitudinal length that is approximately multiples of half wavelength of electromagnetic waves propagating thereon from the first coupler arm to the second coupler arm and along the longitudinal axis of the passive implantable relay module.

4. The passive implantable relay module of claim 1 , wherein the connector portion comprises a first metal core that is sized and shaped to run a particular longitudinal length such that electromagnetic energy that has arrived at the second coupler arm is no less than 50% of electromagnetic energy that has been received at the first coupler arm and along the longitudinal axis of the passive implantable relay module.

5. The passive implantable relay module of claim 1 , wherein the connector portion comprises a first metal core and electromagnetic energy that has arrived at the second coupler arm is at least 10 times greater than when the first metal core is absent.

6. The passive implantable relay module of claim 1 , wherein the connector portion is sized and shaped to have a diameter that is no bigger than 1.8 mm.

7. The passive implantable relay module of claim 6 , wherein the connector portion comprises a first metal core and is sized and shaped to snake through a tubing with a lumen of 1.8 mm or under when the passive implantable relay is implanted inside the subject such that (i) the second coupler arm is placed substantially parallel to the receiving antenna on a passive implantable neural stimulator device and (ii) the second coupler arm is positioned to wirelessly transmit the electromagnetic energy, through non-inductive coupling, to the receiving antenna on the passive wireless neural stimulator device that has been implanted inside the subject, wherein the electromagnetic energy has arrived from the connector portion.

8. The passive implantable relay module of claim 1 , wherein the connector portion comprises a first metal core, and a second metal core sized and shaped to run a longitudinal length comparable to that of the first metal core, and wherein a distal end of the first metal core and a proximal end of the second metal core are positioned to form a parallel overlap but without contacting each other such that when the connector portion is placed inside a magnetic field where the subject is taking an magnetic resonance scan, heating caused by electrical charges accumulated along the connector portion during the magnetic resonance scan is substantially reduced than otherwise.

9. The passive implantable relay module of claim 8 , wherein the parallel overlap runs approximately a half wavelength of electromagnetic waves carrying the electromagnetic energy received at the first coupler arm and from the transmitting antenna located outside the subject's body.

10. The passive implantable relay module of claim 1 , wherein the connector portion comprises a first metal core and the first metal core is made of gold-plated stainless steel.

11. The passive implantable relay module of claim 10 , wherein the connector portion comprises a first dielectric coating surrounding at least portions of the first metal core and the first dielectric coating is made of PolyEtherEtherKetone (PEEK).

12. The passive implantable relay module of claim 1 , wherein the connector portion comprises a first metal core, and a first dielectric coating surrounding at least portions of the first metal core, and is without an outer shield that is made of metal.

13. The passive implantable relay module of claim 1 , wherein the connector portion comprises a first metal core, a first dielectric coating surrounding at least portions of the first metal core, and an outer shield that is made of metal, the outer shield enclosing at least portions of the first dielectric coating.

14. The passive implantable relay module of claim 1 , wherein the first coupler arm includes a first center conductor region, wherein the second coupler arm also includes a second center conductor region.

15. The passive implantable relay module of claim 14 , wherein the first center conductor region is aligned with the transmitting antenna such that linearly polarized electric field is captured by the first center conductor region.

16. The passive implantable relay module of claim 14 , wherein the second center conductor region is aligned with the transmitting antenna such that linearly polarized electric field is captured by the second center conductor region.

17. The passive implantable relay module of claim 14 , wherein the first center conductor region and the second center conductor region are of substantially identical length of approximately 5 mm.

18. The passive implantable relay module of claim 1 , comprising a housing with an antenna lumen to enclose the first coupler arm, the connector portion, and the second coupler arm.

19. The passive implantable relay module of claim 1 , comprising a housing with a stylet lumen to house a guiding device when the passive implantable relay module is being implanted.

20. A method of implanting a passive implantable relay module, the method comprising:

implanting a passive implantable neural stimulator device inside a subject such that electrodes of the passive implantable neural stimulator device are positioned to deliver electric charges to excitable tissue;

inserting a passive implantable relay module by snaking the passive implantable relay module through a tubing such that a distal coupler arm of the passive implantable relay module is placed substantially parallel to a receiving antenna on the passive implantable neural stimulator device; and

placing a proximal coupler arm of the passive implantable relay module underneath the subject's skin such that (i) the proximal coupler arm is configured to receive electromagnetic energy wirelessly and through non-inductive coupling from an external radio frequency pulse generator module placed outside the subject when the external radio frequency pulse generator module is activated, and (ii) the distal coupler arm is configured to wirelessly transmit electromagnetic energy, again through non-inductive coupling, to the receiving antenna on the passive wireless neural stimulator device, thereby wirelessly powering the passive implantable neural stimulator device.

21. The method of claim 20 , wherein inserting a passive implantable relay module comprises snaking the passive implantable relay module through a tubing on the passive implantable neural stimulator device.