Design RFID tag for ID-1 card

Hello,

I have a problem with design antenna to rfid tag used in ID-1 card. I design a rectangular coil for Mifare Classic. I need a information where i can find a resistance of Mifare chip?

I took to my calculation a Resistance a chip: 300 ohm, but i dont know if this is a true value. This is a calue that I received for my coil:

Rectangular coil:
- 4 turn,
- space between path: 0.5 mm,
- width of path: 0.5 mm,
- width of coil: 38mm,
- length: 72 mm,

- resistance of chip: 300 Ohm,
- voltage of chip: 5V (is this ok? )
- capacitance of chip: 17 pF,

Results for copper coil:
- Inductance: 1,673 uH,
- Capacitance (resonance) - 82,342 pF,
- Resistance of antenna: 4,076 Ohm,
- Q - 34,955 ,
- Minimal electromagnetic field strength: 1,425 A/m


I have internal capacitance of chip: 17pF. My resonance capacitance is 82.342 pF. What should I do? Fix a geometry of chip to get a capacitance near 17pF? What about a parasitic capacitance of coil? How can i calculate this?

And what about impedance? I think that should be a 50 Ohm. How can i tune to this impedance?

Sorry for my question but I am a newbie. Someone has a tutorial to design this antenna in sonnet? I think that will help me to improve design process.

Thank for your advice

W.A.