Wireless Charging coil detection issue

Hi,

We are using STEVAL-ISB68WA EVMs to validate Qi based wireless charging functionality for one of our application. It looks like our Qi standard transmitter is not able to detect the ISB68WA receiver, when tried placing on the top of the transmitter coil. What might be the reason for that?

NOTE: We are using standard A10 coil at the transmitter end, which works fine with other receivers.

Is it because the receiver coil is too small to pickup the signals from the transmitter or is it because of some other reason?

Kindly helps us in solving the issue.

Thanks,