Hi,

I'm quite comfortable impedance matching to
large signal series equivalent impedances, when i
get them in data sheets. No problem, even when i
have to extrapolate a bit.

However, sometimes you only get scattering
parameters. So we could use this formula:

Z11=((1+s11)*(1-s22)+s12*s21)/((1-s11)
*(1-s22)-s12*s21)

Etcetera. But i don't wanna do vector
math all the time. And i also don't wanna
graph this gamma on the Smith chart by hand.

So i was wondering if there was a program
out there, that will do this calculation
for you?

Thanks in advance!


Dr. Slick

wrote:
Hi,

I'm quite comfortable impedance matching to
large signal series equivalent impedances, when i
get them in data sheets. No problem, even when i
have to extrapolate a bit.

However, sometimes you only get scattering
parameters. So we could use this formula:

Z11=((1+s11)*(1-s22)+s12*s21)/((1-s11)
*(1-s22)-s12*s21)

Etcetera. But i don't wanna do vector
math all the time. And i also don't wanna
graph this gamma on the Smith chart by hand.

So i was wondering if there was a program
out there, that will do this calculation
for you?

Thanks in advance!


Dr. Slick

Years ago I wrote a program in Basic which does exactly that. If I can
find it I will be happy to email it to you.

bob, w6nbi

--
Remove spam-suppression X from my address

Bob Stein wrote:
wrote:
Hi,

I'm quite comfortable impedance matching to
large signal series equivalent impedances, when i
get them in data sheets. No problem, even when i
have to extrapolate a bit.

However, sometimes you only get scattering
parameters. So we could use this formula:

Z11=((1+s11)*(1-s22)+s12*s21)/((1-s11)
*(1-s22)-s12*s21)

Etcetera. But i don't wanna do vector
math all the time. And i also don't wanna
graph this gamma on the Smith chart by hand.

So i was wondering if there was a program
out there, that will do this calculation
for you?

Thanks in advance!


Dr. Slick

Years ago I wrote a program in Basic which does exactly that. If I
can
find it I will be happy to email it to you.

bob, w6nbi



Thanks Bob, that would be excellent.

As i understand the Z11 formula
i stated, you will still get a vector
solution, so in essence the Z11 will
be a gamma reflection coefficient, or magnitude
(from 0 to 1) with an angle. So on top of that, you
will need to convert this gamma to
the complex series equivalent impedance,
which you can do graphically on the Smith, or
by using:

Gamma(Z11) = (ZL-Zo) / (ZL+Zo)

And letting Zo=characteristic impedance (assume
real! Usually 50 ohms), and then solving for ZL.


Slick