1. Introduction to EM Simulation Microwave Office Training

2. 2EM Simulation EM simulation setup has changed in 7.5. –EM uses drawing layers. Case 1: Draw and Simulate a Structure in the EM Environment. Case 2: Using a Layout Created in the EM Environment in normal layout. Case 3: Importing DXF and GDSII Layouts Into EM. Case 4: Extracting layout from the Schematic Layout.

3. 3EM Simulation The EM Environment Step 1: Open up the project 4Layer_PCB_Start.emp. This is the EM Socket. Projects go in here. To create a project - RC on EM Structures. The various EM simulators - we are using EMSight.

4. 4EM Simulation EM Enclosure Settings The Enclosure menu controls many of the important features of EM: X and Y box dimensions, and grid size. Bulk material properties. Dielectric Layer Setup. The conducting line properties - layer, conductivity, and thickness. EM Layer Mapping (Used when working with schematic layout and artwork cells. Note: Later we will be seeing the Stackup Element for extraction. It is almost the same as the Enclosure (with some extra features).

5. 5EM Simulation EM Enclosure Settings - 2 Sets the x and y dimensions of the enclosing box. The height (z) we set later. Sets the grid in the x and y directions. You want the box size a whole number of cells. Enclosure

6. 6EM Simulation Grid Size Tips Lines should be 3 to 5 cells wide. –Edge couplers might require more. Box size - Don’t have the wall too close to nearest metal... two substrate heights away is good. Make sure gaps / spacing in filters is an integer number of cells. If possible - start on a simple problem you know the answer to - simple bend, open line, 2 coupled lines,... –Gives you an idea how many cells to use. Double your number of cells and see if your answer changes a lot. Note: 1000 unknowns - runs in 30 seconds/frequency. Solution time grows as N 3...10,000 unknowns - 30,000 seconds/frequency. Number of Unknowns.

7. 7EM Simulation EM Enclosure Settings - 3 Material Definitions Adding Dielectrics Conductor Properties Used for Surface Impedances New in 7.5 - Preset values remember materials you added before.

8. 8EM Simulation EM Enclosure Settings - 4 Dielectric Layers Materials can be picked from the list of Dielectrics. Draw scale used for 3D visibility. New in 7.5 - Place the mouse on a layer to see its properties. Can set the top and bottom Boundary Conditions.

9. 9EM Simulation EM Enclosure Settings - 5 Materials Sets the conducting lines properties: The thickness of the line. What it’s made of (from list of Conductors in Material Definitions). Note: Etch Angle and Roughness are reserved for future use. New in 7.5: Perfect Conductor will always exist - made out of material definition - Perfect Conductor.

10. 10EM Simulation EM Enclosure Settings - 2 EM Layer Mapping This controls how drawing layers are mapped to EM layers. We’ll worry about it later. New in 7.5: This mapping is in the Enclosure Options.

11. 11EM Simulation Drawing in the EM Environment To draw in EM: Select an EM Layer. Select Material. Select Conductor or Via. Extent is how many layers down the via extends. New in 7.5: The stackup display shows you the layer you are on.

12. 12EM Simulation Drawing in the EM Environment - 2 Step 2: Draw a line - 60 mils wide - layer 3 to layer 4 connected by a via (50X60mils). Use material - c - as the conductor. Draw Tools New in 7.5: There is not any separate button for vias.

13. 13EM Simulation Drawing in the EM Environment - 3 3D View The 3D view shows the structure to be simulated. New in 7.5: Always check the 3D view - it will only show what is being included in the simulation.

14. 14EM Simulation Drawing in the EM Environment - 4 Adding Edge Ports Step 3: Add an edge port to each of the lines. Select the line. Select the edge port icon, and click at the end of the line. Double click the edge port and use the drag handles to select the deembedding length. EM Structure Layout

15. 15EM Simulation Ports You can double click on a port and change its impedance. Also can change how much power goes into it. Note: This only affects current and antenna pattern viewing. S parameters are not changed. There are 3 kinds of ports: Edge Ports - Like network analyzer hooking up at edges of structure. Via Port - One port to top or bottom of box (ground). Like 1 point probe. Internal Port - Across gap - like 2 point probe. Tip: Be careful! Where is ground for an internal port? There are 3 Webinars in KB on this - EM Simulation: A Look Under the Hood: 1, 2, 3.

16. 16EM Simulation Drawing in the EM Environment - 5 Properties of an EM Shape RC on any shape - Properties. You can change a shape’s material and EM layer. Note: The Mesh Options Tab controls how finely a shape is meshed. You normally don’t change this - unless you want to override default automesh settings. You can see the shape properties in the Lower left corner of the UI.

17. 17EM Simulation Drawing in the EM Environment - 6 Showing Only Active Layer New in 7.5: There are various new viewing options for understanding layers. RC in the stackup display - Hide Shapes on Non-active Layers. In this example - only layer 3 conductors and vias will be visible. Tip: You can use the mouse wheel to go through the layers.

18. 18EM Simulation EM Simulation Options RC to set solver options. RC on project to get individual project options. Some global options under: Options > EM Options. EM Options for an EM Structure This tab is simulator specific.

19. 19EM Simulation EM Simulation Options - 2 Frequency Control Project frequencies can be overridden locally. You can set the meshing frequency if you wish. Tip: Often you want fewer EM frequencies because of long simulation times.

20. 20EM Simulation EM Simulation Options - 3 Advanced Frequency Sweep AFS - simulates over frequency band with (hopefully) fewer frequencies and (hopefully) more accuracy than just set, discrete frequencies.

21. 21EM Simulation EM Simulation Options - 4 AFS adds frequency points up to the maximum - until convergence is reached. You can specify a band besides the default if you want. Note: When AFS is finished, the frequency points displayed in graphing will be the original points in the frequency tab... So - you might want to set at a high number.

22. 22EM Simulation EM and Normal Layout Schematic Layout and Artwork Cells use Drawing layers that have already been named. The EM Mapping file is used to give drawing layers material properties (conductivity and thickness) and layer position. There are a number of scenarios where this is needed: –Importing Artwork cells to EM for simulation. –Using an EM layout in schematic layout. –Extracting a circuit’s schematic layout to EM layout.

23. 23EM Simulation Using an EM Layout in Schematic Layout When we created our EM project - what drawing layers did it use? Remember - If you can see it, it’s a drawing layer! Answer - it autogenerated these drawing layers. Note: All autogenerated EM layers begin in +. So long as we are only in EM - this is fine. But - what happens if we use this layout in the schematic layout?

24. 24EM Simulation Using an EM Layout in Schematic Layout - 2 Step 4: Create a new schematic - EM_as_Sub-circuit. - Add the EM Structure as a sub-circuit. Schematic View Layout View It draws on the error layer. The problem is the schematic layout has no idea where to put the auto- generated layers.

25. 25EM Simulation Using an EM Layout in Schematic Layout - 3 The secret is to understand the EM mapping file. It lives in the LPF file. All layouts - schematic layout, artwork cells, EM projects... have an LPF file. All LPF files have an EM mapping file - it tells the materials and line position in the stackup for each drawing layer. EM Mapping file for EM project - start. These 3 layers have material and EM layer position. Note: Layer number is top of dielectric layer.

26. 26EM Simulation Using an EM Layout in Schematic Layout - 4 Default LPF for project. The schematic layout uses the default project LPF, and its EM Mapping. This is why it doesn’t know what to do with the autogenerated layers... They aren’t even defined in the schematic layout LPF.

27. 27EM Simulation Using an EM Layout in Schematic Layout - 5 To fix the problem - The EM project’s LPF was generated from the project LPF - then the autogenerated layers were added. We fix the project LPF - so that any EM project we create will have the right mapping. Step 5: Modify 4LayerPCB.lpf. Modified default LPF. Note: A common mistake is to misspell the material name.

28. 28EM Simulation Using an EM Layout in Schematic Layout - 6 Step 6: Update the dependent LPFs (i.e. the EM projects created). RC on the LPF in Layer Setup - and Update. You can select the Dependent LPFs to update.

29. 29EM Simulation Using an EM Layout in Schematic Layout - 7 Schematic Layout The EM auto generated layers have disappeared. They aren’t needed. For example, it knows if you want a conductor on em layer 3, you are on drawing layer met2. Note: Any new EM projects will also have this mapping - as they are generated from the default project LPF.

30. 30EM Simulation Options for Viewing Layers There are a variety of viewing options. RC in the drawing layers pane. Options for viewing: Shapes on unmapped layers. Shapes on mapped layers. Shapes on missing layers. I’ve uncloaked all unmapped layers. An X indicates unmapped. Tip: The 3D EM view only shows mapped layers. Good way to see what is really simulating.

31. 31EM Simulation Multiple EM Mapping Files You can have multiple EM Mapping Files. You can create these for the project LPF, or for EM Mapping File for a given project. Different EM Mappings Examples: Switch between lossy lines and perfect conductors. In MMIC - might not want to map to EM all metal layers. Different LPF files.

32. 32EM Simulation Importing DXF and GDSII into EM External World GDSII Libraries DXF Libraries Artwork Cell Layout EM Layout Looks for Model Layers by same name - or creates them. Step 7: Import mypad.dxf. Method 1: Copy and paste the drawing layers. Select the shapes and change the layers. Method 2: Change the EM Mapping file - so can repeatedly use the mapping in the future.

33. 33EM Simulation Method 1: Import and Change the Layers Step 8: Copy the EM project - start. Rename the copy to Via_Sim. - Delete the structures. Tip: One way to make many EM projects with same settings - is to copy an empty EM project. Step 9: Copy and paste the artwork cell - New_DXF_Cell into the EM Project. - You can use Ctrl - C, Ctrl - V.

34. 34EM Simulation Method 1: Import and Change the Layers - 2 It’s placed on the Error layer. You can fix it by selecting the properties of each element... and moving it to the right drawing layer. Step 10: Set the shapes on TopMetal to met1... the shape on Pad to EMLayer 2, Via. Settings for TopMetalSettings for Pad

35. 35EM Simulation Method 1: Import and Change the Layers - 3 To finish it up - you would change the box size, and extend the line and add a port.

36. 36EM Simulation Method 2: Update the EM Mapping in the LPF File Step 11: Create a new EM Mapping - call it PadMap. Step 12: Setup the mapping or Pad and TopMetal. Note: We could have just modified the Default Mapping - but this gives us practice with multiple EM Mappings.

37. 37EM Simulation Method 2: Update the EM Mapping in the LPF File - 2 Step 13: Copy the EM Project - start - rename it to Pad_with_Mapping. - Delete the shapes. Step 14: Update Dependent LPF’s - select only +Pad_with_Mapping.

38. 38EM Simulation Method 2: Update the EM Mapping in the LPF File - 3 You have the EM Mappings from the LPF in the EM project. Select PadMap - and you can now import the shapes.

39. 39EM Simulation EM Extraction Extraction sends selected PCells and other shapes to the EM Socket. Advantages Drawing carried out by the PCells. As schematic layout changes - can keep sending new layout to EM simulator easily. Ports, and deembedding lines are automatically included. S parameter results are automatically brought back into the schematic and re-simulated. Disadvantages Almost too easy! Never see the EM layout. Box can be too small, wrong layers, boundary conditions... Can get off mesh.

40. 40EM Simulation EM Extraction - 2 Step 15: Open up the project double_stub.emp.

41. 41EM Simulation EM Extraction - 3 Make sure the layout is connected. Simulation Results.

42. 42EM Simulation EM Extraction -4 To extract the circuit to EM we need two elements. The Extraction Element Elements > Simulation Control Elements > Substrates The Stackup Element Controls Size of enclosure and mesh Simulator Type What elements are extracted. Controls Layers, Materials,... It’s essentially the same as Enclosure with extra feature of Line Type extractions.

43. 43EM Simulation EM Extraction - 5 Step 16: Add the Extraction block to the schematic and configure it. EM_Doc - The EM Project created. Name - The extraction group name. Extension - The box will be this much bigger than nearest conductor. Note: Put in “ “.

44. 44EM Simulation EM Extraction - 6 Step 17: Configure the Stackup block.

45. 45EM Simulation EM Extraction - 7 Note: When you change the mapping file - you will get a warning... next slide.

46. 46EM Simulation EM Extraction - 8 Line Type Mapping - This can be used as an alternative to EM mapping - when you setting up what EM Layer and Material for a Line Type to use. Note: It is normally used with iNets.

47. 47EM Simulation EM Extraction - 8 The project LPF - will be changed to the new EM Mapping file. Be careful before you do this. Tip: Make a new EM mapping file - before you do this - so you don’t overwrite the original.

48. 48EM Simulation EM Extraction - 9 Step 18: Select all the elements. - RC on properties - enable all of them for extraction under Model Options. Don’t use quotes!

49. 49EM Simulation EM Extraction - 10 Selecting the Extract block shows the elements are enabled for extraction.

50. 50EM Simulation EM Extraction - 11 Step 19: RC on the schematic icon and Add Extraction. The EM project is created. Tip: It’s always a good idea to check things over the first time you extract. Look at the 3D, etc.

51. 51EM Simulation EM Extraction - 12 Step 20: Enable AFS for the EM Project. Simulate - and look at the results in the graph. Note the S parameters are automatically updated.

52. 52EM Simulation EM Extraction - 13 Note: After simulating the EM: I froze the traces: Ctrl - F. Went to the schematic and disabled the Extraction Block. Resimulated. There is a large difference in filter response.

53. 53EM Simulation Viewing the Mesh The mesh is viewed in the 3D view as an annotation. Note: It doesn’t need to simulate to see the mesh.

54. 54EM Simulation Viewing Currents Currents can be viewed as a 3D annotation. Note: You cannot view currents with AFS turned on. I disabled AFS, and simulated at 1 point - 20 GHz.

55. 55EM Simulation Viewing Currents - 2 You can animate it - cycles through phase. EM 3D Layout Toolbar.