# Characterize the coupling coefficient between one power Tx coil and one data Tx coil

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#### bhl3302

##### Full Member level 6
Hi All, my system have a set of power coils and a set of data coils. Ideally, we want the coupling coefficient between the power coil and the data coil to be zero to minimize the interference between them, espcially they are operating in a closed frequency range.

In this paper "Enabling Wireless Powering and Telemetry for Peripheral Nerve Implants" (IEEE Journal of Biomedical and Health Informatics, 2015), the authors mentioned the coupling coefficient between power Tx and data Tx coils should be less than 0.05 to garantee the detection of the data.

Now I have my power Tx coil (760308103307) and data Tx coil (760308101302), both from Wurth. I am wondering is there any way to characterize this coefficient by doing some time/frequency domain test? Or can we have some idea of estinate the coupling coefficient number by reading the datasheet?

Thank you!

#### CataM

Hi All, my system have a set of power coils and a set of data coils. Ideally, we want the coupling coefficient between the power coil and the data coil to be zero to minimize the interference between them, espcially they are operating in a closed frequency range.
What does "closed frequency range" mean ?

Now I have my power Tx coil (760308103307) and data Tx coil (760308101302), both from Wurth. I am wondering is there any way to characterize this coefficient by doing some time/frequency domain test? Or can we have some idea of estinate the coupling coefficient number by reading the datasheet?
By reading the datasheet no. The coupling will depend mainly on the distance between the coils, geomtry of coils, orientation of coils (it is not the same symmetrically and asymmetrically).
Determine it analytically i.e. with pen and paper (or using mathematical tool) is not possible IMO (I am not aware of any article) since your coils have that type of ferrite core.

2 ways come to mind to determine the coupling:
1) Model as exact as possible your coils in a FEM software tool e.g. ANSYS Maxwell or any other and find the coupling.
2) Do it experimentally which is the best way: https://www.daycounter.com/LabBook/Mutual-Inductance.phtml

Last edited:
bhl3302

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