Using layout parameters in Momentum EM simulations

In this application note, we will look at two different ways of using layout parameters for Momentum EM simulations:

  • Use built-in parameters in layout created from standard circuit elements (microstrip line etc.)
  • Parameterize manually drawn layout from rectangles/polygons

We will discuss the use EM results of parameterized blocks in a schematic, with emSetup/emModel views.
A basic understanding of Momentum mesh setup etc. is required. Those details are not discussed again in this document.

Using layout parameters in Momentum EM simulations


Miniaturized Bandpass Filter (AEL layout example)

In this application note, AEL programming is applied to create a fully scalable layout of to the miniaturized band pass filter by Sheng Zhang et al, published in Microwave Journal March 2017.  This fully parametric layout cell can then be used in ADS for analysis, parameter sweep or optimization with Momentum.

Miniaturized Bandpass Filter (AEL layout example)


Create customized artwork cells using AEL code

In this application note, we will look at the basics of AEL programming for customized layout (“artwork”) and how to include that in your ADS project.

ADS: Create customized artwork cells using AEL code


Using Equations and User Defined Functions in ADS

In this appnote, we will look at different ways of using equations in ADS:

  • simple equations “on the fly” in the ADS data display and
  • user defined functions that you can use in data display or optimization for target definitions.

We will also discuss the re-use of custom equations/functions. All these concepts are shown with a simple example.

ADS: Using Equations and User Defined Functions in ADS


ADS: Sweep over many S-Parameter files: look up table or sprintf()?

In this application note, we will look at two methods of sweeping over a list of S-parameter files: using a look up table and using sprintf() string function to build filenames.

Sweep over many S-Parameter files: look up table or sprintf()?


ADS Momentum: SMD Port Calibration

This application note is a simplified version of an earlier global-ground-or-differential-ground appnote,
with a special focus on SMD port calibration in ADS Momentum, and how to use it properly.

ADS Momentum: SMD Port Calibration


Momentum port: global ground or differential?

In Momentum, ports are usually referenced to some infinite ground plane. That global ground physically connects the reference nodes of all ports, and enables return current between the port grounds. There is an option to create ports with an explicit (-) reference node assigned by the user. The appnote discusses both options, and how to interpret simulation results.

Momentum port: global ground or differential?


Edge/Area pins in Momentum EM simulation

This appnote discusses the useful, but widely unknown edge/area pins in Momentum EM simulation, based on a power amplifier PCB example. Edge/area pins are supported in Momentum since ADS 2011, and give us control over the port edge length (for edge ports) or port area (for internal ports inside a polyon).

Edge/Area pins in Momentum EM simulation


ADS: Auto-generate 3D passivation for FEM simulation

In most EM simulations of on-chip layouts, the passivation is assumed planar, so that we can easily simulate it with Sonnet or Momentum. However, in real life the top metal is often coated with a conformal passivation.

In many cases, the accuracy of that planar EM simulation is fine. But how about a more accurate test with the Full-3D FEM solver built into ADS? That’s what this application note is about: configure ADS to automatically build the correct, full 3D passivation for FEM simulation.

EM models with full 3D Passivation for FEM simulation


Merging via arrays in ADS 2012

In RFIC, larger vias are created as via arrays. The size of each single via is usually fixed by the technology rules, and via arrays are created where a larger via cross section is needed. This application note describes efficient modelling of via arrays in Agilent ADS with the Momentum EM solver.

Merging via array in ADS 2012


The ground pin confusion in EM transmission line models

In my EM trainings, I notice that ground nodes in transmission line EM models can cause confusion. Most often, that confusion comes up with RFIC designers, who are used to rather non-ideal ground path behaviour. They often wish to separate the effects in the “signal conductor” of a line from the effects in the “ground conductor”. But the point is … depending on the port setup, it might be impossible to differentiate between them. For more information, have a look at this application note!

The ground pin confusion


RFIC inductor simulation: 1-port or 2-port?

How to simulate RFIC inductors in Momentum, as 1-port or 2-port EM models? Why do we get different results for the Q factor, and which is right?

When EM simulating on-chip inductors, it is not obvious which port configuration is “best”. Depending on the port configuration, the extracted inductor properties can be very different. For more information, have a look at this application note!

RFIC inductor simulation: 1-port or 2-port?


 

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