RFiD coil antenna What is the role?

N&R is RFlLD coil antenna a leading supplier of smart cards and RFDI tags for global system integrators and distributors. We offer a wide range of RFID tags with contact chip or contactless chip (LF, HF, UHF) ,such as ISO CR80 card, wristband, key fob, disc tag, laundry tag, tire tag ect. They are widely applied in different kinds of applications. For examples: access control, smart payment, loyalty system, assets tracking, identifications, time and attendance management.

I know antenna shapes and geometry are dependent on: Frequency (125 Khz in this case) and range of reading (of the tags) and number of turns. Of course many other items, but they are purely derivative from the two I mentioned first.

So I disassembled my rfid reader:

Up to here all done, simple building, now I will desolder the coil antenna, saving it in case of reusing it or take it as a model.

http://www.nfcandrfid.com/products_info/ISO15693-RFID-coil-antenna-315101.html