Should the return loss (S11) be as high as possible ?

[evoplus]

Return loss

Hi,

Could I check the return loss (S11) is preferred to be as high as possible right? Apart from the reason why we want the return loss for example waveguide to be as high as possible is to prevent the signal from reflecting back and cause interferences to the next incoming signals? Is my understanding to this correct?

Are there any more reasons for this?

Thanks

 

[springf2000]

Re: Return loss

the return loss high,it means the reflection is small;
y should make the concept of the return loss clearity,that is the input power substract the input power

 

[fekete]

Re: Return loss

You want to have high return loss numbers because:
- more signal power gets through
- many times the reflected signal goes back to the output of some semiconductor devices and can perturb their proper function (sometimes you need to put an isolator to avoid problems and that, increases costs)
- the interference with the next incoming signal happens only if this returned signal is reflected again back from the previous devices, discontinuities, generator etc.
- the multiple reflections described above can give rise to unwanted resonances that can perturb the generator and also change the “transfer function” from generator to devices.