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Need a help in understanding Bode plotter reading??

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samy555

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I made some experiments on L-network Z matching, first I try the circuit without any match (R1 is source impedance and R2 is the load impedance), and got the following result:

jb13716670981.jpg

Notice: the voltage gain = -0.828 dB @ 100MHz
I repeated the experiment again, but this time using the wattmeter and got:
jb13716670982.jpg


What I was able to understand from the aove is as follows:
dB power gain = 0.5 dB voltage gain
Our pode plotter gave us that the dB voltage gain = -0.828,
so the dB powe gain = -0.414, and that’s mean P_load/P_source = 0.909
So 90.9% of the source power transferred to the Load.

Now I'll introduce the L-impedance match (Which was calculated by someone)
jb13716670983.jpg


Notice: the voltage gain = +3.979 dB @ 100MHz
I repeated the experiment again, but as before using the wattmeter and got:
jb13716670984.jpg


dB power gain = 0.5 dB voltage gain
Our pode plotter gave us that the dB voltage gain = +3.979,
so the dB powe gain = +1.99, and that’s mean P_load/P_source = 1.58
So 158% of the source power transferred to the Load and this is imposible.
The wattmeters show 50% was transfred.
Where the error in my concepts?
Thank you.
 

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