The Challenge is that the frequency of the sensor/coil changes on both EVMs as they move relativ to their target. And at some point the frequencies of the sensors cross. They vary between 3,5 MHz and 4,6 MHz for my Application.
As you can see the the band is 1,1 MHz. The bands must be very thoughtful calculated to never overlap.
Just a warning for everybody thinking of an array of coils. The stray Field of the coils may be larger than you initially thought of...
Regards Torgeir