All four are all 2 element ell networks. If the values have been
calculated correctly each one would provide the required match. (1) has
low-pass characteristics. (4) is a high-pass network. The other two
probably have less frequency selectivity. A Pi matching network could
also do the job. The typical shunt C, series L, shunt C, is a stronger
low-pass filter, so it will attenuate harmonics better. If an element
in a Pi filter is removed, giving it an ell topology, it will not
provide the same match or filtering characteristic. The values of the
remaining two components would both need to be recalculated. There are
theoretically an infinite number of networks that can provide a given
impedance transformation. They will all have different frequency
responses. Even if you stick with a shunt C, series L, shunt C Pi
network, there are many possible sets of component values that will
provide the same impedance transformation, but with different
(transmission) frequency responses. Usually a network Q value is first
chosen.
Dave
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On 2025-03-13 22:16, shlomo537678 via groups.io wrote:
Hi All.
I need to build a Pi Network for my circuit as shown in the fig below.
1741926237187.png
So I have a 'Pi Matching Network' in my circuit. The datasheet asked me to build a Pi Matching Network. ( You know, how there is a series component, a source shunt component and a Load shunt component. )
Anyway, my VNA keeps telling me this: The measured load impedance is 31.9-58.5j.
The VNA is automatically generating these four groups below ( group 1 thru 4 ) of available matching parameters on the screen:
1. 5.24pF capacitor for source shunt and 28.8nH inductor in series.
Does that mean, this group does not need a Load Shunt at all? Does this mean that the proper tuning has been achieved with just a capacitor for source shunt and an inductor in series?
2. 23.1nH inductor for source shunt and 12nH inductor in series.
Does that mean, this group does not need a Load Shunt at all? Does this mean that the proper tuning has been achieved with just a inductor for source shunt and an inductor in series?
3. 97.5nH inductor for load shunt and 23.3nH inductor in series.
Does that mean, this group does not need a Source Shunt at all? Does this mean that the proper tuning has been achieved with just a inductor for load shunt and an inductor in series?
4. 15.3nH inductor for load shunt and 5.21pF capacitor in series.
Does that mean, this group does not need a Source Shunt at all? Does this mean that the proper tuning has been achieved with just a inductor for load shunt and a capacitor in series?
If the answer is yes to all the 4 above questions, then I still cant believe that a 'Pi matching Network' can exist with 1 of the 3 components totally missing.
Ty for your reply!
