How do I determine the ground node connection for a Component?

Which ground node connection you choose for your Component depends on the type of model you are using and the configuration of the Component. The ground node connection is selected in the Component Properties dialog box.

The ground node connection is used by em when analyzing your circuit and determines what ground reference is used when de-embedding the component. You must select a ground node connection for both the Data File model and the S-Parameter model. Note that the Ideal Component model setting does not require a ground node connection. The settings are described below.

All component ports reference a common local ground. that is not attached to the global ground (Sonnet box).

Choose this option if your component does not have a ground reference, or if there are no shunt elements in your component model or measured data.

Examples of when you would use this option include:

A series RL equivalent circuit
S-Parameter data that was measured without any pads.

All the component ports are globally grounded to the Sonnet box. To do this, a via is automatically created which connects to the top or bottom of the Sonnet box. If the path of the via to the box top or bottom is blocked by other metal in your circuit, emreports a simulation error.

Choose this option if your component model or measured data includes shunt elements and you want the component's ground reference to be connected to the Sonnet box. In this case, Sonnet includes the shunt elements in the simulation.

Examples of when this ground node connection should be used are:

S-parameter data that includes pads or other coupling to ground
Transistor data that includes a via in the model/measurement.

If you have Sonnet Box selected as the ground node connection for a component, the port symbol has a small arrow pointing downward as shown below.

The ground reference of your component is connected to a user defined location in your geometry. You may specify as many ground terminals as you need. This ground node connection is only available when your component is a Data File type.

Examples of when this ground node connection should be used:

Transistor data without parasitics to ground, but with a ground path included in the Sonnet structure
A multi-pin module with one or more grounds.