Return Loss: a positive quantity (what does it means)

[microwave79]

Dear All

Pls refer to the article (Definition and Misuse of Return Loss) by T.S.Bird (E-I-C, IEEE TAP). Can anyone please explain (with example) how it can be correctly used. This is a serious matter and must be considered by every Microstrip antenna designer.

Pls check it here:

**broken link removed** ( free document)

Thanks

 

[Borber]

In the nature of log function is that log of number greater than 1 is positive, log of number smaller than 1 is negative. Guess the result of log(1).

 

[microwave79]

But how can it be represented in db vs frequency plot

 

[E Kafeman]

PDF says something like:
/
Positive dB Loss = Loss
Negative dB Loss = Gain
Since a long time is interpretation of "Return Loss" misused.
Stop that, at least if you want paper published in IEEE.
/

Compare:
Positive dB Gain = Gain
Negative dB Gain = Loss