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Multiple Edge Coupled Striplines (EM Quasi-Static) (X=3 to 16): SXCLIN

Symbol

Summary

A set of circuit components models sections of multiple edge coupled striplines in a two-layer dielectric substrate. Line conductors are sandwiched between top and bottom dielectric layers. This model allows arbitrary unequal heights of dielectric layers. The model name includes the number of coupled lines (>=3): S3CLIN, S4CLIN etc up to S16CLIN. A backing metallic ground plane and metallic cover are always present.

Topology

Parameters

Name Description Unit Type Default
ID Name Text TL1
W1 Width of microstrip line Length W[1]
W2 Width of microstrip line Length W[1]
Wn, n=3..XX - number of lines Width of microstrip line Length W[1]
S1 Spacing between lines Length W[1]
Sn, n=2..XX - number of lines Spacing between lines Length W[1]
L Physical length Length L[1]
Acc Accuracy parameter   1
SSUBL Substrate name Text [2]

[1] User-modifiable default. Modify by editing under $DEFAULT_VALUES in the default.lpf file in the root installation directory.

[2] If only one SSUBL is present in the schematic, this substrate is automatically used. If multiple SSUBL substrate definitions are present, you must specify which to use.

Implementation Details

Model implementation is based on the EM Quasi-Static technique described in [1]. It accounts for losses in metal and in substrate dielectric. Dispersion is partly included.

These circuit components model sections of multiple edge coupled striplines. The models allow the thickness and characteristics of dielectrics at both sides of striplines to be different. S3CLIN models three edge-coupled striplines, S4CLIN - four, S5CLIN - five, S6CLIN - six, and so on up to S16CLIN. Two edge-coupled striplines are modeled by S2CLIN; documentation for this model is provided separately.

The parameters W1..WX (strip widths), S1.. SX (gaps between strips), and L (line length) are dimensions entered in the default length units. Here X stands for the number of coupled lines that is different for each model.

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

The SSUBL parameter specifies the two-layered stripline substrate element which defines additional cross-sectional parameters of the transmission line. If blank, a default is used.

These components do not impose restrictions on the conductor thickness (the thickness may be zero, positive, or negative). Negative thickness means that the conductor is recessed into the substrate.

The components account for losses in metal and in substrate dielectric. Dispersion is not included.

NOTE: The implementation of EM Quasi-Static models relies heavily 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.

Layout

This element does not have an assigned layout cell. You can assign artwork cells to any element. See “Assigning Artwork Cells to Layout of Schematic Elements” for details.

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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