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To run this script

Select Script → Project → DC_Model_Check from the Menus.

Or in Version 13 or higher you can run the utility directly from this page using this button.

Description

This script will check each data file and EM structure for passivity and impedance at DC to look for problems. This script will run simulations but only for the item being analysed. This script will work best if your project has been simulated before it is run. The result is an html page summarizing any issues with an explaination of what was checked. The top information includes:

This page displays results of checks to determine if Data Files and EM structures are well behaved at DC. This becomes an issue when using either of these with nonlinear simulators which much always solve for the circuit at DC first. If you are only doing linear analysis, the DC values are not a problem.

It checks the following:

  1. Passivity of the structure at DC. Values should be > -0.0001

  2. Real part of the impedance at each port at DC. Looking for negative values < -100000. This implies that large negative values are okay.

  3. Angle of reflection coefficient at each port at DC. Looking for values not 0 or 180 (+- 0.5) degrees. Complex impedances are not used in the simulators at DC, but they show extrapolation or measurement issues.

The first line for each document or sweep in a document lists the overall health of data. The additional informaiton listed supports the overall health checks. This file lists the real part of the impedance and the angle of gamma looking into each port for inspection. Any values determined to be bad will be printed in RED

Additional Details:

  1. Disabled EM documents are not checked and will be listed as such.

  2. Checks are done to determine if data files are for active devices. The worst case passivity is checked and if less than -1 assumes device is active. Results will be shown in BLUE.

Below shows a picture of some sample results.