C_LINTYP

	C_LINTYP Data Item Coplanar Linetype Data Definition Perameters Notes
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Coplanar Linetype Data Definition

The geometrical dimensions of a coplanar transmission line and the metal levels of the center line and ground planes are defined in the C_LINTYP data item.

Parameters

Parameter	Discreption	Range of Usage
W	Center conductor width	n/2.DL (n=2,3,4,...)
S	Slot between center line and ground planes	n/2.DL (n=1,2,3,...)
GW	Width of ground planes (GW= 0 ® infinite ground planes)	n/2.DL (n=1,2,3,...)
CEN_MET	Identification of metal level for the center line	1 or 2 (DEFAULT-Foundry)
GND_MET	Identification of metal level for the ground planes	1 or 2 (DEFAULT-Foundry)

Notes

The line parameters (W, S and GW) must be chosen in a way that metallization corners lie on the grid (see Range of Usage). However, if the user specify a maximum deviation from grid size ACC (see C_GRID for details), the simulator can adapt the incompatible structure parameters into the grid by changing these parameter slightly (warnings will be reported). For ACC=0 (no deviation from grid) the simulator reports error and the next compatible value will be recommended in the error message. Note that these changes are not considered by automatic layout generation.
If the parameter GW is set to 0, infinite ground plans are assumed. This means that the ground planes are connected to the electric walls at the right and left side of the shielding box.
The width of ground planes GW (if GW ¹ 0) effects the line characteristics. The following diagram shows this effect on characteristic impedance ZL. The minimum value for GW should be GW=d (d=W+2S) in order to keep the effect of finite ground planes small.
The Parameter CEN_MET and GND_MET define the metal level of the center conductor and the ground strips respectively. COPLAN for Libra is able to handle more than 1 metal level. The number of metal levels depends on the currently selected foundry. Two different metal levels can be used in case of DEFAULT foundry.
If DEFAULT foundry is selected, the integer value 1 for CEN_MET (or GND_MET) indicates the metal layer 1 in C_TECH data item (parameters t1 and roh1) while the value 2 is used for the metal layer 2 in C_TECH data item (parameters t2 and roh2). Both levels may have different thickness and different resistivities, which are defined by the parameters t and roh in C_TECH.
In present version, GND_MET is used for layout generation only. For the simulation, GND_MET is set always equal to CEN_MET.