PrimCalc is a helpful tool for designing primitives. It allows for
two-way design, with synthesis using a simple iterative design
approach- some variables are free and the others are fixed.
As
an example, for transmission lines such as microstrip, the
primitive’s arguments are on one side of the transform- things that
describe the physical properties. On the other side of the transform
are the impedance (Z0); the effective permittivity (eps_re); and the
conductor, dielectric, and total loss (alpha_c, alpha_d, and
alpha).
The first time PrimCalc is run on a primitive (such as
microstrip/mcurve.xml) it will create a template for input and output
of PrimCalc (mcurve.pci). After that, PrimCalc will remember the last
values entered.
For a standard installation, the Mason models
used in PrimCalc should be located at: "C:\Documents and
Settings\All Users\Application Data\CircuitMason\mason_models"
Designing from Physical Properties to Electrical Properties
Enter in the desired values on the left, with no boxes checked, and "Calc".
Designing from Electrical Properties to Physical Properties
Designing from electrical properties requires some initial guesses
on the left column; this can be from a previous run. Leaving boxes
blank is a bad idea.
Check those boxes on the right column
that you want to define: perhaps the line impedance and the line
length. Check those boxes on the left column that you would like to
be free: perhaps the line width and line length. You can synthesize
based on one or more parameters on each side. Try not to
over-specify.
