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Open Stripline With End Effect (Closed Form): SLEF




Name Description Unit Type Default
ID Element ID Text SL1
W Conductor width Length W[1]
L Conductor length Length L[1]
SSUB Substrate definition 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 SSUB is present in the schematic, this substrate is automatically used. If multiple SSUB substrate definitions are present, the user must specify.

Implementation Details

This circuit component models an open circuited length of Stripline Transmission Line including the end effect. The model assumes a TEM (Transverse Electric Magnetic) mode of propagation and incorporates the effects of dielectric and conductive losses. The parameters W (Strip Width) and L (Strip Length) are lengths entered in the default length units. The parameter SSUB specifies the Stripline Substrate element, which defines additional cross sectional parameters of the transmission line. This model also warns of the possibility of higher order propagating modes if they exist.


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.


Zo>94.25/(εr)1/2 (for T≠0) with Zo= Characteristic Impedance of Trans Line.

T/B≤0.1 Recommended

Rho≤100 Recommended


[1] H.A. Wheeler, "Transmission-Line Properties of a Strip Line Between Parallel Planes", IEEE Trans on Microwave Theory and Techniques, Vol. MTT-26, No. 11, November 1978 p.866-876

[2] S.B. Cohn, "Characteristic Impedance of the Shielded-Strip Transmission Line", IRE Transactions MTT, July 1954 p. 52-55

[3] H.A. Wheeler, "Formulas for the Skin Effect", Proceedings of the IRE September, 1942 p.412-424

[4] K.C. Gupta "Computer-Aided Design of Microwave Circuits", Artech House1981 p.60

[5] A.A. Oliner, "Equivalent Circuits for Discontinuities in Balanced Strip Transmission Line" IRE Transactions on Microwave Theory and Techniques, March 1955 p.134-143

[6] H.M. Altschuler and A.A. Oliner, "Discontinuities in the Center Conductor of Symmetric Strip Transmission Line", IRE Transactions on Microwave Theory and Techniques, May 1960 p.328-339

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