Best Practices for Efficient and Effective Planar EM Simulation
4 www.cadence.com/go/awr
The autoport setting can also use more sophisticated port types when working with ports near each other. These cases
usually arise with surface-mount parts on boards when there is a gap in the microstrip line, and two ports are placed at the
edges of the gap. The resulting S-parameters are placed in a schematic and a model of the part is then attached to the ports
(Figure 3).
The trouble is that the normal ground reference straps on the two ports will result in the ports interacting, resulting in an
invalid calibration. Therefore, grouped ports are created, wherein the calibration structure includes both ports and their
coupling. The autoport setting automatically set up the ports as grouped when they are close enough together. Grouped port
settings can be set manually in one of two menus: either an individual port menu (double click on a port to see the menu),
which has a group setting area, or under the menu Edit > Port Properties, where the settings for all ports in a project can be
used (Figure 3).
Figure 3: Autoports used for a gap in a microstrip line (top left), preview geometry with grouped de-embedding with straps (bottom left), menu
for one port (top right), and menu for all ports (bottom right)
