Via Simulation Models   

There are three simulation models available for via objects in Momentum-GX in ADS 2006A:

The Lumped Model can be used to more efficiently simulate contact via’s (the main purpose of which is to provide electrical or mechanical contact). The 3D Distributed Model yields a full 3D modeling of all the components of the via currents (including the horizontal via currents) and can be used to more accurately simulate the electrical behaviour of signal via’s.

2D Distributed Model   

Lumped Model   Click here to show related information on EEsof Web site!

The internal impedance (resistance and internal inductance) of the via follow from the application of the surface impedance concept for a uniform vertical current distribution on the via. That is, we have:

For via mask layers specificed by a conductivity, the surface impedance Zs is calculated using the single-sided skin effect formula. Hence, the frequency dependent skin effects (yielding a higher resistance and a lower internal inductance as frequency increases) are included in the lumped via model. For via mask layers specified by an impedance, the frequency dependent skin effects are NOT included.

3D Distributed Model   

Selection of Via Model

Default via model is defined in the Momentum Analysis dialog “Simulation Options” page (the default for the analysis is the planar “2D-model”).

The model may be defined for each substrate (dielectric) layer in Layout properties dialog window, “Layer page”, “Via Model” column, defined for dielectric layers (see Layer page).
 Default in the page means using Momentum Analysis model.