Unlike the example with the capacitance matrix in the Model library, you have to assign non-zero values to all your ports if you want to make use of the port sweep feature.
Assign, for example, 1 V to every port and COMSOL will use 1 V at the firtst port and 0 V at the remaining three ports in step 1. In Step 2 it will use 1 V at port #2 and 0 V at ports #1, #3 and #4. And so on.
In electrostatics, on the contrary, it is necessary to assign 1 V to one port and 0 V to the others and COMSOL will sweep the 1 V through all the ports.
This difference is hard to find out, if you start at the Model library example...
Assign, for example, 1 V to every port and COMSOL will use 1 V at the firtst port and 0 V at the remaining three ports in step 1. In Step 2 it will use 1 V at port #2 and 0 V at ports #1, #3 and #4. And so on.
In electrostatics, on the contrary, it is necessary to assign 1 V to one port and 0 V to the others and COMSOL will sweep the 1 V through all the ports.
This difference is hard to find out, if you start at the Model library example...
