Which input impedance is correct for use in V^2/R in RFIC design

Hi all,my team member is just simulating one RFIC design and need to know the impedance of the chip model to confirm the Vrms of RF carrier.From some papers, he has got the input impedance of the differential ports of the chip model, but the impedance has two values which are in r+j type and Rin//Cin type of course two types are the same and could be transfered to each other.BUT,BUT,the problem is which type impedance is better or correct to be used as the denominator of V^2/R.

For the formula P=V^2/R, P is got from known input RF power in dBm,then the numerator V(Vrms of RF carrier)will be calculated when denominator R is confirmed. The question is R=r or R=Rin? j and Cin could be cancelled by matching.

thank u!

If Zin is complex, Dissipated Power will be complex too.If Cin will be cancelled by matching, in this case Rin will be used to obtain Pin so that the power will be entered into device..

Thanks!
I mean for example,if the input impedance is 1000R//5pF which is equal to 1-j32 Ohm@1GHz,when calculate the Pin=Vin^2/Zin,Zin is 1000 or 1(the imag part,5pF or -j32 will be cancelled by matching)?

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Thanks!
I mean for example,if the input impedance is 1000R//5pF which is equal to 1-j32 Ohm@1GHz,when calculate the Pin=Vin^2/Zin,Zin is 1000 or 1(the imag part,5pF or -j32 will be cancelled by matching)?