Calculating a Proximity Net
If you are using NETEX to extract the conductors for a net or nets and you plan to use the data to create a SPICE equivalent model of the layout, then you will also be interested in nearby conductors/nets that capacitively couple to your selected nets. We call these proximity nets.
the two pink nets are the ones to analyze. Other conductors (even on other layers) will influence the capacitive coupling.
NETEX can grab all such conductors if instructed to do so. It then aggregates all of those into a single group we call the "proximity net". Your 3D field solver can then "ground" the proximity net in order to calculate the fringing capacitance.
To direct NETEX to calculate a proximity net you must do two things:
How it Works
The illustration below shows this in detail. NET1 (dark grey) and NET2 (dark blue) are the ones selected for analysis.
In the above example, to analyze nets 1 and 2 and to get the nearby metal (say within 5 um) we would put into our test.cfg configuration file:
UNITS UM EXPANSION 5.0 EXTRACT BYNAME COUPLED_SET1.GDS net1 net2 ENDEXTRACT
and our command line would include
netexmgr test.gds TOP -coupled -cfg:test.cfg