Object - Metal Properties
Selecting Object - Metal Properties opens the Planar Polygon Properties dialog box which allows you to modify the metal type, fill type and subsection size associated with the selected polygon(s). This command only appears in the menu if at least one metal polygon is selected in your circuit. The Metal Object tool bar is also displayed when you select this command.
This dialog box is also opened by clicking on the Meshing Properties button in the Technology Layer Editor for a Metal Technology Layer. If you are modifying the meshing properties of a Metal Technology Layer, any changes will affect the parameters of all metal polygons inheriting their meshing properties from this Metal Technology Layer.
NOTE: If multiple objects are selected which have different parameters, the entry ''Mixed'' appears in the pertinent text entry box. Changes made in the Properties dialog box will affect the parameters of all selected polygons.
Tech Layer: If you wish to associate a metal polygon with a Metal Technology Layer, you may do so by selecting the desired Tech Layer from this drop list. If you want this metal polygon to be independent of any Technology Layers, then select <None> from this drop list. This field does not appear when editing the properties of metal polygons in a project containing no Metal Technology Layers, or when editing the meshing properties for a Metal Technology Layer. If you wish to edit the properties of the Technology Layer, click on the Edit button to the right to open the Technology Layers dialog box. Any changes made to the Technology Layer affects all of the metal polygons associated with the layer.
Properties Control (Local/Inherit): If you wish the selected polygon(s) to use the same material and meshing properties as the Technology Layer selected in the Tech Layer drop list, select Inherit from this drop list. If you wish the metal polygon to have unique properties, select Local from this drop list. Note that when a Technology Layer is selected in the Tech Layer drop list, the properties control is automatically set to Inherit but may be changed. If the Tech Layer drop list is set to <None>, then this drop list is always set to Local. This drop list only appears if the Tech Layer drop list is present.
If a Technology Layer Editor is selected in the Tech Layer drop list and the properties control is set to Local, then the polygon is located in the metal level to which the Technology Layer is assigned. The polygon is also included in an export to a drawing layer or stream. However, in the Sonnet project, the polygon retains its own unique properties which can differ from the material and meshing properties of the Technology Layer to which it is associated.
Metal: Choose a planar metal type from this drop list. Changing the planar metal type changes only the metalization loss. The polygon is still on the same physical level; i.e., it is still between the same two layers of dielectric. This drop list is only enabled if the properties control is set to Local or not present. If you wish to create a new planar metal type, click on the New button to the right to open the Planar Metal Editor dialog box which you may use to create a new metal type. If you wish to edit the presently selected metal type, click on the Edit button to the right to open the Planar Metal Editor dialog box and edit the properties of the metal type.
A new project initially contains only one planar metal type "Lossless". If you have not set up additional planar metal types in the Materials page of the Circuit Settings dialog box, then the pull-down menu only presents one choice of "Lossless".
Fill Type: The "fill type" of a polygon is defined as the type of subsection used by em. This drop list is only enabled if the properties control is set to Local or not present. For a detailed discussion of Fill types, please refer to the Subsectioning Chapter in the Sonnet User's Guide.
The three options are defined as follows:
Staircase Provides the best rectangular fit to the metalization edge.
Diagonal Allows triangular as well as rectangular subsections
Conformal This applies conformal meshing to your polygons. This allows for larger conformal sections which model curved edges more efficiently.
Level: This drop list displays the metal level on which the selected metal polygon(s) are presently placed. If you wish to move the polygon(s) to a different level, select the desired level from this drop list. The polygon(s) are moved to the selected level but maintain their relative position in the x,y plane. This drop list is only enabled when the selected polygons are independent (none are assigned to a Technology Layer).
Subsectioning Controls: Edit the X Min, X Max, Y Min and Y Max text entry boxes and the Edge Mesh drop list to set the subsectioning for the polygon(s). First time users should leave the values set to the default values (X Min=1, Y Min=1, X Max=100, Y Max=100, and Edge Mesh=On). Refer to the Subsectioning chapter in the Sonnet User's Guide for a detailed explanation of these controls.
Include Subsections: Select the orientation of subsections created when the polygon is meshed by the analysis engine, em. The default setting is to mesh the polygon in both the X and the Y directions, which in turn, allows current to flow in both the X and Y directions. Under special circumstances you may wish to limit the direction of current flow on a polygon to either the X or Y direction exclusively, and this meshing control allows you to accomplish that.
Conformal Mesh Subsectioning Control
Maximum Length: If you wish to set a maximum length for a conformal section, click on the Maximum Length checkbox and enter the desired length in the text entry box to the right. This is useful in reducing the size of your conformal sections to ensure higher accuracy. The default length of a conformal section is 1/20 of the wavelength of the subsectioning frequency. These controls are only enabled if the Fill Type is set to Conformal and if the properties control is set to Local or not present.
