I am a rookie in RF, Here is how I think of the loss of power between point A to point B (two points of the transmission line). First, not all the power can "get on" the transmission line, some will return to where it came from, due to the matching problem, that is return loss, even if some power can "get on" the line it will also loss some of its power during the way, from point A to point B, on the transmission line, this is insertion loss (it can be caused copper loss, dielectric loss, radiation loss etc.). If this is the case, how can I calculate out the power on the Point B. if the input power is Pi, return loss is -15dB, insersion loss is -5dB, how much is the Output power Po (power on the point B)?
You should just use insertion loss Pb/Pa = 10^(S21/10) = 10^(-5/10)
Return losses are effectively included in the insertion loss
Energy conservation results in 10^(S21/10) + 10^(S11/10)
@Nikolay Pavlov ,,, Thanks for your answer, I thought if the power provided by the source is Pa, then after return loss the input power will be Pa+, then after insertion loss output power is the ratio of Pa+ instead of Pa.
Thanks again.
Here is another computation:
http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1446.0
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