Where To Find This Example
AWR Version 13
AWR Version 12
This example demonstrates the ability to associate flylines with polygons in layout. In other words, a dumb polygon can behave like an iNet. This feature serves two purposes: (1) To be able to simulate and account for the effects of hand-drawn shapes in a circuit's layout, and (2) To remove any unwanted flylines to make a layout more DRC correct.
This project demonstrates how the shape iNets feature works and also shows some of the different types of polygons that can be associated with flylines. It also compares standard closed form models with their shape iNet equivalents. 2D Mesh annotations were added to the EM structures to show how the shapes are being meshed by AXIEM.
In the layout view of this schematic, there are instructions on how to associate a shape with a flyline. In order to include the effects of the shape in simulation, an EXTRACT block must be added to the schematic, and the wire must be added to the Extract Group (default name is "EM_Extract"). The STACKUP referenced by the EXTRACT block is located in the Global Definitions page, along with an MSUB block. If a measurement is made on this schematic, for example S21, the shape will be simulated using the EM Solver of choice.
Note: Shape iNets will only simulate with shape-based simulator such as AXIEM. It will not work for path-based simulators such as ACE.
The layout view of this schematic shows an ellipse that has been associated with a flyline. If you drag the ellipse and drop it so that it is not overlapping the MLIN's, you will see the connectivity. If you simulate the project, an EM structure called "EM_Ellipse" will be created, and S21 of this structure is plotted the graph called "Ellipse".
Path and Path_Model
These two schematics show two ways of simulating a microstrip path. "Path_Model" shows an MTRACE2 element which can be viewed in the layout view of the schematic. "Path" shows the shape iNet approach where a hand-drawn path is associated with a flyline and extracted to EMSight. The results are compared in the graph called "Path". There is a small difference due to the general limitations of a closed form model and the coupling between parallel segments of the path, which are not accounted for with the MTRACE2 model.
In the layout view of this schematic, you can see that an unusually shaped polygon has been drawn and associated with a flyline. The structure is extracted to an EM structure called "EM_Polygon_Jagged" and the results are plotted on the graph called "Polygon_Jagged".
Polygon_Tee and Polygon_Tee_Model
These two schematics show a comparison between two different methods of simulating a microstrip tee. "Polygon_Tee_Model" uses schematic models, and "Polygon_Tee" uses shape iNets. The graph called "Polygon_Tee" compares the two methods.