When a component or object that has a footprint is placed in the layout or in a schematic, HFSS must map the layers in the component object to the layers that have been defined for the design.
- In a mapping, each layer in the component is either merged with an existing layer in the design or inserted as a new layer in the design.
- The mapping is controlled by the Merge Layers window. You can specify (with the “Always Show Layer Merging window” Layout Editor option; see Layout Editor Options) the Merge Layers window is to be displayed every time a component is placed (the default), or you can have the window display only when mapping of layers cannot be done automatically.
- Automatic mapping can be performed when the design has no layers defined; in this case, all the layers in the component can be inserted as new layers to be added to the design. Automatic mapping is also possible when there is only one choice available for merging layers (e.g., if you have selected the “Top” signal layers as the active layer in the layout , then place a microstrip component (which has only one signal layer associated with it), HFSS maps the object layer to the active layer. If the “Always Show Layer Merging window” option has been deactivated, the automatic mapping is performed and no window appears.).
- When automatic mapping is not possible or when automatic mapping has been deactivated by turning on the “Always Show Layer Merging window” option, the Merge Layers window appears after a component has been selected but before it can be placed in the layout or schematic.
- The window shows the object layers on the left and the design layout layers on the right. From the preceding example, the object has just one layer (Top) while the layout has three layers (Trace, Dielectric, and Ground).
- When an object layer is adjacent to a layout layer (e.g., the Top and Trace layers), the M button is displayed, and the layers are merged.
- When an object layer is adjacent to a blank cell on the layout, the I button is displayed, and the object layer are inserted.
- Clicking on an M or I button toggles the layer between the Merge state and the Insert state. An error occurs if you try to change an Insert layer to a Merge layer when no layers are free for merging.
- Click+drag an object layer to a different vertical position. Changing position retains the Merge or Insert state. If an Insert layer is dragged, the layout layers rearrange to leave an empty cell adjacent to the Insert layer. If a Merge layer is dragged, it snaps adjacent to the nearest free layout layer.
- Check the Flip Source Layers area to invert the order of the object layers (the order of the layout layers in not changed) (e.g., use this operation can be used to match the layers of a soldered-on object (signal, solder, assembly) on the top to the bottom of a two-sided board).
- When the layer mapping is set up as chosen, click Merge Layers to execute the mapping. The component is now attached to the cursor for placement in the layout or schematic.
- Clicking Cancel cancels the placement of the component.