360°-->lamda
You are correct that one turn on the Smith chart is lambda/2. That's also shown on the outermost scale, which ranges from 0 to 0.5
https://de.wikipedia.org/wiki/Smith-Diagramm#/media/Datei:Smith_chart_gen.svg
Yes I know but by doing this (360°-->lamda, 30°--->30°*(lamda/360), so L=lamda/12) also gives us correct physical length of the line, isn't it?
Thanks, I understand. So, as long as eps_r=1 I can use this.Only for lines with eps_r=1, both are the same.
Why is this?In the Smith chart, a line with 30° electrical length will turn 60° in the Smith chart.
Why is this?
That is the electrical length I got from smith chart utility, so I think it is the electrical length parameter of the line.That's what seemed unclear in your first question, if the 30° was for the electrical length parameter of the line or for the rotation angle in the Smith chart.
But If I have matched condition, then I will not have reflected portion. In that case, shouldn't it be 30° only?Because the signal travels 30° thru the line, and the reflected portion another 30° on the way back.
I hope you meant "Note the conversion from electrical length (30°) to physical length (lambda * 30°/360°)"Note the conversion from electrical length (lambda * 30/360) to physical length.
I'll stop here, because you seem to misunderstand my posts and my use of the term "physical length".
Wrong.On a transmission line,
if we take standing wave then the distance between two voltage maxima or minima is lamda/2, which is 360°.
Right. This is round-trip.So lamda equal to 720° degree on smith chart.
Simply you can not understand basic wave equation.So here I am using 360° as lamda.
Where am I making mistake?
No.But If I have matched condition,
then I will not have reflected portion.
In that case, shouldn't it be 30° only?
- frequency
- your electrical length in degree
- effective permittivity of your line
effective permittivity of your line=4.1 F/m
Maybe you misunderstood the question, I asked for permittivity (epsilon_r), not capacitance.
I know what you meant from beginning related to epsilon_r.
frequency-1 GHz
your electrical length in degree=41 degree
effective permittivity =4.1 F/m
360°-->lamda,
30°--->30°*(lamda/360) so L=lamda/12. So here I am using 360° as lamda. Where am I making mistake?
Wrong.
It is 180degree.
In the Smith chart, a line with 30° electrical length will turn 60° in the Smith chart. But in transmission, it has 30° phase, of course.
Simply you can not understand basic wave equation.
You can not understand oneway-trip and round-trip at all.
S11 and S22 undergo round-trip.
S21 and S12 undergo oneway-trip.
β=2*pi/λ
Oneway trip : exp(-j*β*L)
Round trip : exp(-j*2*β*L), This is a phase rotation in smith chart.
You can not understand very basic things at all.*Taken from https://nptel.ac.in/courses/117101057/slides 2/5.3.html. Say Figure 2.
Indeed, the rotation on smith chart is 360°, when the length of the line is lamda/2.
Phase differece for L=λ/2 is 180degree not 360degree.
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