Sonnet User's Guide - Sonnet Software

Chapter 14 Circuit Subdivision
Subdividing Your Circuit
The actual subdividing of your circuit into separate geometry subprojects and a
master netlist project is performed by the software. You enter the desired names
for the master netlist and geometry subprojects. You may also automatically add
feedlines of lossless metal to any ports generated in the subprojects.
Feedlines should be added when discontinuities contained in sections of your
source circuit need to be moved away from the boxwall to prevent interaction between
the boxwalls and the discontinuity. The use of feedlines are optional; if you
choose to add a feedline, you may use the suggested length calculated by the software
or input your own value. By default, the software creates feedlines using the
suggested length.
When the subdivide is executed, Sonnet creates a geometry subproject for each
section of the circuit in which you placed the subdividers. It also creates a master
netlist that connects the geometry subprojects together to produce an equivalent
circuit for the original geometry project that you subdivided.
Each of the geometry subprojects uses the properties of the original circuit: cell
size, dielectric layers, dielectric and metal materials, analysis setup, etc. Therefore,
all the geometry subprojects contain the same analysis setup with the same
analysis frequencies specified.
Analyzing Your Subdivided Circuit
To obtain the desired response data, edit the analysis setup for the master netlist
so that all of the desired analysis frequencies are specified. Each of the geometry
subprojects are set up with the coarser resolution of analysis frequencies. When
the netlist is analyzed, em runs the geometry project analyses first to produce response
data for each part of the network. Then the analysis of the whole network
is executed. Em interpolates to produce data for frequency points in between those
available from the analysis of the geometry subprojects.
If properly subdivided, the results of the netlist analysis should provide an accurate
solution for your difficult to handle circuit using fewer resources. The use of
circuit subdivision is demonstrated in Chapter 15 "Circuit Subdivision Tutorial"
on page 227.
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