Advanced Options Dialog Box

Clicking on the Advanced button in the Options section of the Analysis Setup dialog box opens the Advanced Options dialog box which allows you to set up the de-embedding control, the sub-project control, and the Adaptive Band Synthesis resolution control as well as additional command line options for use by Sonnet technical support.

Geometry Project Only

De-embedding Control

Each port in a circuit analyzed by em introduces a discontinuity into the analysis results. In addition, any transmission lines that might be present introduce phase shift, and possibly, impedance mismatch and loss. Depending upon the nature of your analysis, this may or may not be desirable. De-embedding is the process by which the port discontinuity and transmission line effects are removed from the analysis results. This option is set by default. For more details about de-embedding, please see ''De-embedding'' in the Sonnet User's Guide.

Box Resonance Info

Select this checkbox to output box resonance info during an analysis. If a potential box resonance is detected, a warning is output in the analysis monitor. For a detailed discussion of box resonance, please see ''Package Resonances'' in the Sonnet User's Guide.

Q-Factor Accuracy

Select this checkbox to increase the accuracy of the Q-factor when ABS is used. Normally ABS uses S-parameters to determine convergence. When this option is used, ABS uses both the S-parameters and Q-factor for convergence criteria. This option should be used whenever you plan on viewing/calculating Q-factor, but could require more discrete frequencies.

ABS Caching Level

The ABS caching level determines if and how much of the ABS caching data is stored in your project. The levels are detailed below.

None: Select this option if you do not wish to store any ABS cache data in your project. If this option is selected and you stop an ABS analysis before completion, the only data available is the data calculated for the discrete data points. When you resubmit the ABS job, the cache data will need to be recalculated. Thus, the analysis must start all over again.

Stop/Restart: Select this option to store the ABS cache data while an ABS analysis is running. This allows you to stop an ABS analysis and restart it at a later time without losing the data from the processing done before the stop. This option deletes the cache data when convergence is reached and the ABS analysis is completed. This is the default setting.

Multi-Sweep plus Stop/Restart: Selecting this cache level saves the ABS cache data for every analysis performed on the project. This saves you processing time on any subsequent ABS analyses but be aware that the cache data will be calculated for any analysis of the project including non-ABS types of analysis, increasing the project size. This option should be used when you think you might want to re-analyze the project, using different ABS ranges or settings.

It is important when using this option that all your analyses use the same subsectioning frequency. This ensures that any pre-existing ABS cache data can be used in the present analysis The default setting used to determine the subsectioning frequency is to use the highest frequency from the present analysis job. If you perform multiple sweeps over different frequency bands then the cache data from one run will be invalid for the next, since the subsectioning frequency would be different. In order to avoid this you should use the controls for the subsectioning frequency found in the Advanced Subsectioning dialog box to ensure that the same frequency is used for all analyses.

ABS Frequency Resolution per Sweep

The resolution provides the minimum value of the gap between data points in an adaptive band synthesis (ABS). This can be calculated automatically by em or input by the user.

Automatic: The resolution of the frequency band used in an ABS analysis is determined by the analysis engine, em. This is the default setting. The automatic setting provides approximately 300 frequency points in the band.

Manual: If you wish to set the resolution for an ABS analysis, select this radio button and enter the desired resolution in the adjacent text entry box. The units for this value are the presently selected frequency units for the project.

There are several things to be aware of when using the manual setting for the ABS resolution. Coarse resolution does not speed things up. Once a rational polynomial is found to ''fit'' the solution, calculating the adaptive data uses very little processing time. A really coarse resolution could produce bad results by not allowing the ABS algorithm to analyze at the needed discrete frequencies. Fine resolution does not slow down the analysis unless the number of frequency points in the band is above approximately 1000 - 3000 points. A step size resulting in at least 50 points and less than 2000 points is recommended.

Force Analysis

Selecting this checkbox forces em to perform an analysis at frequencies for which data already exists. Care should be exercised with this run option especially on larger circuits whose analysis time are significant.

Geometry and Netlist Projects

Additional Options

This text entry box allows you to enter additional analysis run options. The available options are as follows:

-p1: Perform the analysis using the release 7.0 matrix fill algorithm when ABS is not turned on. This option may only be used for a geometry project.

-p2: Perform the analysis using the release 7.0 matrix fill algorithm for all analyses including adaptive sweeps (ABS). This option may only be used for a geometry project.

The 7.0 algorithm is faster than the 8.0 algorithm but has higher precision error. Therefore, running with these options is not normally recommended, especially when an adaptive sweep (ABS) is enabled. These options may be useful when analyzing circuits with many layers at high frequencies, where the user is sure there are no precision problems.

-q<threshold>: Enable quad precision below <threshold> Hz. Note that the threshold is specified in Hz regardless of the frequency unit used in the project. If you do not specify a <threshold>, quad precision is turned on for all frequencies. Using this option may cause your analysis to take up to 100X longer to run; therefore, this option should only be used when absolutely necessary. This option may only be used for a geometry project.

Note: It is not recommended that you set your threshold inside an ABS band when performing an adaptive sweep.