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(Obsolete) Microstrip Gap in Conductor (Closed Form): MGAP



This element is OBSOLETE and is replaced by the Microstrip Gap (EM Quasi-Static) (MGAP2) or Microstrip Gap (EM Based) (MGAPX) element.


MGAP$ is a Microstrip iCell and has no parameters. See “Intelligent Cells (iCells)” for more information.

Name Description Unit Type Default
ID Name Text TL#[1]
W Conductor width Length W[2]
S Gap width Length W[2]
MSUB Substrate definition Text MSUB[3]

[1] # is automatically incremented as additional TL Element ID's are added to the schematic.

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

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

Implementation Details

W (width of microstrip conductor), S (length of the gap) are entered in the default length units.

MSUB indicates the name of the MSUB element to use for substrate characteristics. If blank, a default is used.

Model is represented by a symmetric π-circuit comprising two frequency-independent capacitances; it provides accuracy about 7% accurate in the ranges

0.1 < S/W < 1.

2.5 < εr < 10

where εr is the substrate relative permittivity.

NOTE: This model is considered obsolete due to low accuracy; MGAP2 is recommended for use instead MGAP.


This element does not have a visual layout cell. The layout cell creates a gap between the two microstrip or stripline elements that connect to each side. The size of the gap is determined by the S parameter. Since there is no layer to draw, linetypes do not apply. You can select the layout cell to snap the microstrip or stripline elements to it.


[1] R. Garg, I.Bahl, "Microstrip Discontinuities," International Journal of Electronics, vol. 45, No. 1, 1978, pp. 81-87.

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