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(Obsolete) Multi-Layer Meander Microstrip Line (Configurable): MTRACEM

Symbol

Summary

There is no active replacement for this OBSOLETE element. MTRACEM is a user-configurable, multi-layer meander trace. This model is similar to the single-layer MTRACE model, except that the electrical models used for the transmission lines and discontinuities, as well as how their layout cells are rendered, are user-defined using an Element Process Utility. A multilayer substrate, NSUB, must be present in the project to use this model. Contact Cadence® for more information about how to set up a customized Element Process Utility.

This model is available with MWO-228, MWO-328, and ANO-xx9 configurations only.

Parameters

Name Description Unit Type Default
ID Element ID Text TL1
NSUB Substrate definition Text NSUB#[1]
*NC Network node count   2
*XY XY-point array   {0}
*FR From index array   {1}
*WS Segment width array   {40}
*LT Segment line type array   {0}
*Impl Implemented   1
*LM Type Line model type (vector - length equal to number of lines)   {0}
*DM Type Discontinuity model types (vector - length equal to number of discontinuities)   {0}
*ARG1 Model parameter 1 - see Help (vector   {0}
*ARG2 Model parameter 2 - see Help (vector)   {0}
*ARG3 Model parameter 3 - see Help (vector)   {0}
*ARG4 Model parameter 4- see Help (vector)   {0}
*ModLvl Net modeling level   Level 3 -Distributed (tx lines only)
*EmExt EM extractor   EM Extractor

[1] Modify only if schematic contains multiple substrates. See the “Using Elements With Model Blocks” for details.

* indicates a secondary parameter

Parameter Restrictions and Recommendations

There are additional parameters associated with this model that are not included in the previous table. These parameters display on the Parameters tab of the Element Options dialog box and are set and used by the model; they are not intended for user editing.

Implementation Details

MTRACEM is a "smart" aggregate model whose aggregated elements are assembled dynamically. Based on the particular configuration, MTRACEM automatically figures out which models to aggregate. For example, MTRACEM can figure out whether a straight section of transmission line should be considered microstrip, stripline, embedded microstrip, etc. and aggregate the appropriate transmission line model. Similarly, it can determine whether a discontinuity should be a via, bend, taper, etc. and aggregate the appropriate discontinuity model. MTRACEM uses two things to determine what a model should be: the NSUB substrate definition and the Element Process Utility that is specified by the ProcUtil parameter of the NSUB. Contact Cadence for information about setting up a customized Element Process Utility. You can also see the NSUB documentation for more information.

MTRACEM must always start and end with a transmission line section. Also, line sections and discontinuities must alternate (for example, line-discontinuity-line-discontinuity-line).

Layout

This element is considered obsolete. You should use iNets and the ACE simulator to obtain the same functionality.

Recommendations for Use

The following steps must be complete before you can use MTRACEM correctly:

  1. Place an MTRACEM element in the schematic.

  2. Place an NSUB substrate in the schematic (or in the Global Definitions window).

  3. Specify the Element Process Utility by setting the "ProcUtil" parameter on the NSUB.

  4. Set the remaining NSUB parameters so that they correspond to the specified process utility (ideally, the MTRACEM is used in conjunction with a process library. In this case, an NSUB can be set up and included with the library as an XML component, so no user set-up is necessary- the XML NSUB element can simply be dropped into the schematic and used as is).

  5. Import the LPF file associated with the Element Process Utility.

If any of these steps are not complete, error messages may result during electrical simulation and the layout may not render correctly.

Graphical Editing:

The following information is also found in the AWR Microwave Office Layout Guide .

In general, you use the mouse to edit multilayer trace elements. Double-clicking an element activates blue diamonds that manipulate the bends and lines.

On one straight segment there are three diamonds. The outside diamonds control the length of the segment and the middle diamond controls bend manipulation. The diamonds are manipulated by placing the mouse over the diamond to activate an arrow cursor.

To move the diamond, click and drag the arrow cursor to another position and then release the mouse button.

Add a Bend

To add a bend to any line segment, select the multilayer trace element in the Layout View. While holding down the Shift key, click and drag the middle diamond to another position and then release the mouse button. Before you release the mouse button an outline of the new multilayer trace displays.

The following figure shows the completed bend.

Moving a Line Segment

When moving a segment in a multiple segment trace, the length of the segment being moved always stays constant while the other segments may vary in length. Click and drag the middle diamond of the segment between the two bends to another position and then release the mouse button. The following two figures illustrate moving an interior segment.

The following two figures illustrate moving an end segment.

The following figure shows the new length and bend position.

When there are more than two bends in the multilayer trace you can change the bend position and the length in a "trombone" action. Simply click and drag the middle diamond of an interior segment to another position and then release the mouse button. Note in the following two figures that the middle section length remains constant while the other two segments vary in length.

Rotate a Segment

To rotate the end segment of a multilayer trace, press Ctrl and click and drag the end of a multilayer trace that has at least one bend in it.

When grid snap is on, the angle of rotation is only placed on a Snap angle increment as specified on the Layout Options dialog box Layout tab in the Rotation Snap option. (Choose Options > Layout Options to open the Layout Options dialog box.)

Multilayer Trace Routing

You can route the multilayer trace layout cell using the TRACE routing command. The TRACE routing command routes the multilayer trace from a center line path that is drawn with the mouse (or by using coordinate entry). The TRACE routing starts by double-clicking the multilayer trace to put it into edit mode. When the multilayer trace is in edit mode, the grab diamonds are visible (NOTE: For an iNet, the only diamonds that are not eligible for TRACE routing are the diamonds that display at a junction of three or more segments).

Multilayer TRACE Routing at the Start Point

If the TRACE routing is started at the beginning of a path, a center line path can be drawn as shown in the following figure. If you press the Tab key or Space bar while drawing the center line, a Coordinate Entry dialog box opens to allow coordinate entry of the center line points. You can also use gravity points when drawing the center line. You draw the center line by clicking at each of the desired vertex points, and complete it by double-clicking for the last point, or clicking on the same point twice.

After the center line path drawing is complete, the multilayer trace element routes itself to the center line path. The routing is not always exactly on the center line because there are other constraints that may need to be satisfied. Note that performing a route at the starting path point completely replaces the old trace.

Multilayer TRACE Routing at the End Point

If the TRACE routing is started at the end of a path, the center line path that is drawn is appended to the existing path.

Multilayer TRACE Routing at an Interior Point

If the TRACE routing is started at an interior point, one of two things occurs, depending on where the routing ends. If the routing ends at another existing diamond, the portion of the trace between the starting and ending diamonds is replaced with the path specified by the new routing. This allows for replacing interior segments without affecting other segments of the trace.

If the routing ends at a point that is not already part of the existing trace, the portion of the trace after the starting diamond is replaced with the path specified by the new routing. This allows for replacing a trace past a certain point without affecting the beginning segments of the trace.

Multilayer TRACE Routing on Multiple Line Types

The multilayer trace can be routed to multiple line types. When you double-click a diamond to start the routing, note that the cursor displays delta x, delta y, length, and line type. To change the line type while routing, press the Shift key, then use the mouse wheel to scroll through all of the possible line types. If the routing begins at a diamond that is located at an intersection of two different line types, the line type that initially displays next to the cursor is the line type of the segment that goes into the diamond.

The 3D view of the layout shows that after routing on multiple line types, the proper transitions (vias in this case) are added.

Multilayer TRACE Manual Editing

You can edit the components that make up the multilayer trace. To display the dialog box for editing, right-click on the layout object in the Layout View and choose Shape Properties to display the Cell Options dialog box.

The Lines tab displays all of the individual line segments that make up the trace or net in a grid format. Each row of the grid represents a single line segment and its properties, including line type, line width, line length, and model type. Model Type is the type of model to use to electrically model the particular line segment. For example, if an Element Process Utility specifies two possibilities for a line segment, such as a closed-form model and an EM-based model, you can select which one to use.

In the Discontinuity column each line segment is paired with the discontinuity that exists at the end of the line segment. To see the direction for a particular segment, click on the line segment row in the grid and observe the layout. A red arrow displays over the line segment and points from the start to end. The following figure shows the arrow that displays on the fourth line segment when you click the fourth row in the grid:

To edit the properties of a discontinuity at the end of a line segment, click on the button in the Discontinuity column for that particular line segment to display the Discontinuity Properties dialog box.

Here you can edit the parameters associated with the discontinuity. The discontinuity model type is similar to the line segment model type previously discussed, except that it applies to a discontinuity instead of a line segment.

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