TMS3705: TMS3705 in use with UCC27524

Hello,

I use the TMS3705FDRQ1 together with UCC27524A, within the referencedesign described in manual SCBA021 "TMS3705 Range Extender Power Solution Using UCC27424"

I tried one antennasize with 200x300mm , with two different  antennawires (different antenna Q factor) one with 0,5qmm the other with 0,09qmm and with four inductancevalues ,

251uH (Cres=5,nF), 281uH (Cres=5,0nF) 426uH (Cres=3,3nF), 521uH (Cres=2,7nF)

Finaly I have eight antennas with 200x300mm.

The antennevoltagesuppy vary from 5V up to 12V. I can also measure different antennvoltages from 75V up to 390V (Peak to Peak)

With antennavoltagesupply 5V I get with both antennas and they have different Q,  the same readingdistance with animaleartag around 23cm 

weather they have different peak to peak antennavoltages.  The readingdistance with 23cm is with all eight antennas the same.

With increasing the antennavoltage  up to 12V it is the some appereance a readingdistance from 31cm is the result also with all eight antennas

I tryed also one antenna with 300x600mm here is the maximum readingdistance also 32cm with the animaleartag.

Normaly here should be a different, when antennas are in use with different Q factor. Why is there no different, or what is here the limiting factor ?

A animaleartag has up to 70cm readingdistange with longrangereader S2000 and bigger antenna.

thanks :-)