how to find phase constant
I have this small problem, I've simulated a 2-way equal power divider with variable length feeds, now when the Data Table is seen its shows both magnitude and phase of the ports along with sweep frequency, my doubt is how do I relate this phase with the phase constant beta, actually my doubt is whether this phase (of transmission S21 & S31 along with refleciotn S11) given in Data Table can be used along with the length of the feed (individual feeds) to calculate Beta (phase constant) or do we require some other information apart from this phase to measure Beta, or I'm completely wrong when I'm doing so?
or simply tell me how do I calculate phase constant beta (β) from my simulated result
Plzz people help me out with this if you can,
thanx in advance.
What software do you use ?
What do you see on the data table (S11,S21,Magnitude ,phase ?)
Hiiiiiiiiiii Pushhead,
I'm using HFSS v9.0 for my simulations and I'm seeing the magnituce and phase for S11, S21, S31 only.
Now can u tell me, how to find the phase constant beta from the table.
thanx in advance.
Hello again,
Since i'm not using the same software, I can just explain to you the "standard"
procedure :
1st option :
Take the S21 (or S31) angle at your design goal frequency.
measure the length from port 1 to port 2 ( in case of S31 port1 to port3 ).
solve φ = β×(length) where φ is radians. You'll probably have to reduce some 360° cycles until your angle is 0 ≤φ≤ 360 , or , -180≤φ≤180 or the range your software provides you.
2nd option :
If your software provides you with a TDR ( Time Domain Reflections ), follow the
peak of the input signal and peak of the output signal, measure the time difference
and solve : Δt = (length)/(phase velocity).
then : β = 2pi*frequency/(phase velocity).
hope this helps,
P.