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IRS: New resonator topology miniaturized for transmission device and inductive coupling allows volume reduction

Domain Health and wellbeing

Technology Bio-embedded devices


How to increase the magnetic field without increasing the electric field to maximize the magnetic coupling for energy transfer and miniaturization to reduce the volume ?

Innovative solution

The invention reduces losses and improves the PTE by using a ceramic material with high permittivity to confine the electric field. The transfer of energy is done only by intense magnetic coupling.

This allows to reduce the size of the EMD.


  • Implantable electronic medical devices (EMD) (Alimentation Stimulation)
  • Electroceuticals


  • Reduction in the volume used (antenna + electrode).
  • Improvement of the transmitted power. Increase of the communication distance while stimulation capability.


A measurement campaign with a new prototype manufactured by 3D micro-printing is in progress.

How it works

By de-coupling radiofrequency (used for wireless power transfer) and low-frequency signal (used for electrical stimulation), it is possible to have them flow on the same electrode.

However, the radiofrequency coil is subject to poor performances when placed at the interface of body tissue.

Therefore the device uses a ceramic body made of a material having a higher permittivity than that of the surrounding environment and with low dielectric loss.

Indeed, the present invention provides a new structure for the coil comprising:

  • a cylindrical ceramic main body having a thread on its surface;
  • a conductive wire (copper, gold) being wound around the main body according to the thread;

This topology enables having more electric field in a preferred and lower volume.

The innovation improves the efficiency and yield longer transmission distance.


For frequencies of the order of 100 MHz, a gain of a factor of 3 of the quality criterion Q has been demonstrated. This means that there will be 3 times more current in the coil than the magnetic field will be three times stronger.


Developed by Simon HEMOUR 

IMS (CNRS, université de Bordeaux, Bordeaux INP)



19 01114




License and/or R&D collaboration

with a Medical Device Enterprise





+33 (0)5 33 51 43 24



Ref: #SBE_2018-041_202007

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