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6.7.3. Debugging the Structure

Unintentional opens or shorts in structures are a common occurrence. One tool to aid in locating such a problem is the conducting net support in Analyst. This support allows the mesh to be colored by electrically conducting nets. You can control the visibility of each of these nets.

To create an annotation:

  1. On the Structure ribbon in the Post-Processing group, click New Annotation and choose Mesh from the drop-down menu. The Edit Properties dialog box displays.

  2. On the Display tab, change Color By to Conducting Net, as shown in the following figure, then click OK to close the dialog box.

  3. Expand the Browser node for your mesh annotation (Annotation_1), and expand the Conducting Nets node below it. The view displays as shown in the following figure.

    Notice that there are 4 nets (1 is identified as nonconducting). This is incorrect; there should only be 2 actual conducting nets - one representing the inner coax conductor and the microstrip and the other the outer coax conductor and ground plane. You need to find the cause of the problem.

  4. To avoid rendering overlaps, hide the geometry by toggling off the light bulbs for the Geometry and Conducting Nets > Nonconducting nodes in the Browser. The view displays as shown in the following figure.

  5. The outer coax conductor and ground plane display electrically connected since they are both colored red, so turn off that net by toggling off the light bulb for the Net_3 node.

  6. You now notice that the inner coax conductor is colored orange (Net_1) and the microstrip is colored blue (Net_2). If you rotate the model and zoom in to look more closely at the connection between the inner coax conductor and the microstrip, you notice a gap, as shown in the following figure.

    That is the cause for the incorrect results. To measure the size of the gap, turn on the light bulb for the geometry, then turn off the light bulb for the mesh annotation. Turn off the light bulbs for the outer (air) box and the outer cylinder for the coax. Rotate the geometry so the face of the coax conductor is visible. In the structure view toolbar, click the Calculations and Queries drop down menu and select Minumum Distance Between Entities:

    Click to select the face of the conductor, then click the microstrip. Press Enter or click Done. The width of the gap is displayed:

    You made a mistake when defining the overlap variable - it should have had a value of "0.1 cm" (positive) and NOT "-0.1 cm" (negative).

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