Cell

The electromagnetic analysis starts by automatically subdividing your circuit into small rectangular subsections. Em uses variable size subsections. Small subsections are used where needed and larger subsections are used where the analysis does not need small subsections.

A "cell" is the basic building block of all subsections, and each subsection is "built" from one or more cells. Thus a subsection may be as small as one cell or may be multiple cells long or wide. All subsections must be an integer number of cells. Thus the "dimensions" of a cell determine the minimum subsection size.

The smaller the subsections are made, the more accurate the result is and the longer it takes to get the result. Therefore, there is a trade off between accuracy and processing time to be considered when setting the cell size. The project editor gives you a measure of control over the subsection size. For a detailed discussion of subsectioning, please see Subsectioning in the Sonnet User’s Guide.

Note that the dimensions of a cell need not be a "round" number. For example, if you want to analyze a line that is 9.5 mils wide, you need not set your cell dimension to 0.5 mils. You may want to set it to 4.75 mils (9.5 mils divided by 2) or 3.16667 mils (9.5 mils divided by 3). This will speed up the analysis because fewer subsections will be used. Also, the width of the cell does not need to be the same as the length.

When viewing your substrate, notice that the project editor displays a grid made up of regularly spaced dots. The distance between each grid point is the cell size.