I'm trying to create an optimizable impedance that is always at the edge of the Smith chart, but has a variable angle. I've created a couple of test equations in a Data Display, and the results make no sense.

The results are:

Temp1 = 3.1415 (so far, so good)

Temp2 = 0.998 + j0.055 (inaccurate & wrong sign)

(expected -1 +j0)

Temp3 = -2.586E-13 + j1.823E3 (nonsense)

What I think I'm doing is taking the angle (in degrees), converting it to radians, and then using the polar() function to make a complex reflection coefficient with magnitude 1. Then the zin() function should give me the impedance I need, which should be ~zero Ohms. The real part is close (although how it gets that from the polar conversion is beyond me).

I'm a bit rusty at this stuff, so it's possible I'm missing something fundamental and silly. I'm certainly not getting what I need.

As an added bit of excitment, when I put an equation with zin() into a variable block on my schematic, it claims zin is an unresolved reference.

Any suggestions/corrections?

Thanks!

Doug White

**Eqn**Angle=180**Eqn**Temp1=rad(Angle)**Eqn**Temp2=polar(1,rad(Angle))**Eqn**Temp3=zin((polar(1,rad(Angle))),50)The results are:

Temp1 = 3.1415 (so far, so good)

Temp2 = 0.998 + j0.055 (inaccurate & wrong sign)

(expected -1 +j0)

Temp3 = -2.586E-13 + j1.823E3 (nonsense)

What I think I'm doing is taking the angle (in degrees), converting it to radians, and then using the polar() function to make a complex reflection coefficient with magnitude 1. Then the zin() function should give me the impedance I need, which should be ~zero Ohms. The real part is close (although how it gets that from the polar conversion is beyond me).

I'm a bit rusty at this stuff, so it's possible I'm missing something fundamental and silly. I'm certainly not getting what I need.

As an added bit of excitment, when I put an equation with zin() into a variable block on my schematic, it claims zin is an unresolved reference.

Any suggestions/corrections?

Thanks!

Doug White

The polar() function assumes the angle is in degrees. Hence you should not convert the angles to radians.

Another way to create an impedance that varies around the edge of the smith chart is this:

You can sweep/optimize the value of the phase, ph, to rotate the impedance around the Smith chart.