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2 Embedded Edge Coupled Microstrip Lines (EM Quasi-Static): MEM2LIN

Symbol

Topology

Parameters

Name Description Unit Type Default
ID Element ID Text TL1
W1 Conductor 1 width - Nodes 1&&3 Length W[1]
W2 Conductor 2 width - Nodes 2&4 Length W[1]
S Gap width conductors 1&2 Length 40 um
L Conductor length Length L[1]
Acc Accuracy parameter   1
MSUB4 Substrate definition Text MSUB4#[2]

[1] User-modifiable default. Modify by editing under $DEFAULT_VALUES in the default.lpf file in the root installation directory. See AWR Microwave Office Layout Guide for details.

[2] If only one MSUB4 is present in the schematic, this substrate is automatically used. If multiple MSUB4 substrate definitions are present, the user must specify.

Implementation Details

This circuit component models a section of two coupled microstrip lines embedded into a four layered substrate.

The parameters W1, W2 (strips widths), S(spacing between lines) and L (line length) are dimensions entered in the default length units.

The parameter Acc is the accuracy parameter (1≤AccParam≤10). The default value for Acc is 1. If Acc is less than 1 or greater than 10 it is sets automatically to 2. Larger value of Acc increase density of mesh used in computations. Accuracy of model parameters may gain slightly from increasing Acc at the expense of noticeable growth of computation time. As a rule of thumb, good trade-off between accuracy and computation time is to set Acc to 1.

The parameter MSUB4 specifies the four-layer microstrip substrate element, which defines additional cross sectional parameters of the transmission line. If blank, a default is used. Conductors are implied to reside at the boundary between layer 2 and layer 3.

This component doesn't impose restrictions on the conductor thickness (thickness may be zero, positive, or negative). Negative thickness means that the conductor is recessed into the layer 3.

MEM2LIN may be used to implement various kinds of coupled striplines: buried, coated, inverted, and suspended simply by selecting relevant dielectric constants and thicknesses.

Covered microstrip line may be implemented with SEM2LIN (embedded coupled striplines).

The component accounts for losses in metal and in substrate dielectric. Dispersion is not included.

Layout

This element uses line types to determine its layout. By default, the layout uses the first line type defined in your Layout Process File (LPF). You can change the element to use any of the line types configured in your process:

  1. Select the item in the layout.

  2. Right-click and choose Shape Properties to display the Cell Options dialog box.

  3. Click the Layout tab and select a Line Type.

  4. Click OK to use the new line type in the layout.

See “Cell Options Dialog Box: Layout Tab ” for Cell Options dialog box Layout tab details.

See “The Layout Process File (LPF)” for more information on editing Layout Process Files (LPFs) and to learn about adding or editing line types.

Recommendation

When implementing suspended, coated etc. lines don't make, if possible, thickness of any layer too small in comparison with other layers: the calculation time may noticeably grow.

Warning

The implementation of EM Quasi-Static models heavily relies on the involved numerical algorithms. This may lead to the noticeable increase of computation time for some schematics that employ many models of this kind.

References

[1] M.B. Bazdar, A.R. Djordjevic, R.F. Harrington, and T.K. Sarkar, "Evaluation of quasi-static matrix parameters for multiconductor transmission lines using Galerkin's method," IEEE Trans. Microwave Theory Tech., vol. MTT-42, July 1994, pp. 1223-1228.

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