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[Rfdesign]

dear friends
hi
I embedded an antenna in a lossy medium and I know the S11 and deliver power 1w but i don't know, how should I calculate the radiated power?
the return loss Figure is resonated at 402MHz to -20dB .
Is this solution sorrect?
S11=10log(P(ref)/P(inc)))=>
-20=10log(P(reflected)/1w)=>P(reflected)=0.01w
P(inc)=P(radiated)+P(ref)=>P(radiated)=0.99

but I have a lossy medium in which the antenna is located.that is
P(radiated)=P(pure_radiation)+P(Loss)
I know the SAR value 135(mw/g), but I don't know how should I calculate the P(Loss) and then the pure value of the P(pure_radiation).
so ,what's the solution?

[bigSteve]

You can't calculate radiated power from s11. For instance, if you measure a 50 Ohm resistor, the vswr=1, the s11=0 (-inf dB), but the radiated power is 0.

You need to know the delivered power and antenna efficiency to calculate the radiated power.

SAR isn't well correlated with radiated power. The SAR values are measured when the antenna is pressed up against a lossy medium, which tunes the antenna low, and lowers the antenna efficiency. In addition, radiated efficiency is calculated over an entire sphere, whereas SAR only measures power that goes into the medium the antenna is up against.

So, there's no quick way to do it.

[Rfdesign]