Coplanar Open C_OPEN

Symbol :

Illustration :

Parameters :

L = Length of transmission line connected to the coplanar open end.
GAP = Spacing between the open end and ground planes (only for TYPE= Ground_Connection)
WG = Width of the ground plane at the open end. (WG=0 ® infinite ground plane, only for TYPE=Ground_Connection)
TYPE = Type of open (see illustration)
C_LTYP = ID of coplanar transmission line applied at port 1
C_SUB = ID of coplanar substrate definition
C_GRID = ID of simulation control data
TEMP = ID of element temperature definition used for noise computation

Range of Usage :

GAP = 0.5.n.DL* n=1,2,3,...
WG = 0.5.n.DL* n=1,2,3,...
* ) see C_GRID for information on DL

Notes/Equations/References :

The C_OPEN module represents an open at the end of a coplanar line. The dimensions of the line connected to the open are defined in data item addressed by C_ LTYP. L is the length of the connected coplanar line.



GAP is the distance between the open end and ground planes and WG is the extension of the ground plane at the end of line.



A negative value for L can be meaningful during the simulation. In such cases, the automated layout generation works incorrectly and the generated layout has to be edited manually. The minimum value for L depends on the metal layer oversize in the currently selected C_LAYER. In case of DEFAULT foundry, L should be greater than or equal to max(|cond_os|, |cond2_os|).



For WG =0, infinite ground plane at the open end is assumed.



TYPE indicates the form of open end. There are two types of open ends as shown in the above illustration.



If TYPE= No_Ground_Connection is selected, the parameters WG and GAP are ignored.



If L1 and L2 in selected C_GRID are not set to –1 or –2 (auto sizing), the minimum values for L1 and L2 are:



L1_min=W+2S+2GW

L2_min=8DL+GAP+WG



See notations in chapter 4 (Important Note!) for the correct selection of C_LTYP.

Equivalent Circuit :

For the modeling of the C_OPEN element, an equivalent capacitance is used. The value of this capacitance is derived from quasi-static FD-calculations. The connected line at the port is modeled as a C_LIN element and is represented by its characteristic impedance Z_L and phase constant b. There is no limitation due to the length of connected line (L)

Layout :

If TYPE=No_Ground_Connection and L=0, only a port symbol is generated as layout. For L=0 and TYPE=Ground_Connection only the ground planes at the end of line is drawn.



If the parameter GW_DEF in C_PROCES is set to a positive non-zero value, this value is used as ground width for layout generation.