Hi Najwa Faudzi ,

provided L and C are parallel, the total admittance Y is the sum of the susceptances BL and BC. In the complex plane, BL points in the direction of -90° and BC in +90°, i.e. they point into exactly opposite directions. In the resonant case, |BL| = |BC|, so the sum = Y would be zero if there were no losses; accordingly, the impedance Z would be infinite.

Of course, a lossless antenna would be pointless because the purpose of a (transmitting) antenna is to spread some non-reactive power into the surrounding. This power loss can be modeled by a resistor in parallel to L and C. In your case, this resistance lies in the range of 6.5 kOhm to 15.5 kOhm. But this is neither an internal resistance of the chip nor the resistance of an additional real resistor.

Neglecting losses in the conductors, you can estimate the transmitted power based on this resistance: P = V2peak / (2 R), @ 3.6 V and 10 kOhm about 650 microW.

If your circuit provides the given coil inductance LRES and external resonance capacitance CTune, it should work fine.

Thank you very much sir Joerg Fricke for your explanation..

Following on from Joerg Fricke

The impedance of the tank circuit is root(L/C) which is about 200 ohms. The Q of this circuit is 30, so the (equivalent) parallel loss resistance of the tank circuit is about 6 kohm, which is close to the range of impedance given - perhaps it shouldn't say impedance.

Hi Malcolm White

Thank you for your further explanation.. Yes it is quite confusing with the terms impedance that they are using in the datasheet..

Hello,

Few papers are attached for your help.

All the Best,

Thanks,