5:1 AC Step Down Transformer

Grumpy_Mike: No not at the frequencies we are talking about.

I double checked the skin depth equation for copper, and that confirms what you said. On the other hand, I contacted Agilent about the resistance measurement function on my LCR meter and they confirmed that it measures only resistance. Reactance is a separate function. Is it possible that the wire my RFID coils are made from is not copper?..I'll contact the company to confirm this.

Is it possible that the wire my RFID coils are made from is not copper?

No.