C_SUB

	C_SUB Data Item Coplanar Substrate Data Definition Perameters Notes
COPLAN Software Description List of Topics Download Manual

Coplanar Substrate Data Definition

C_SUB contains the parameters for a three layered substrate. For each layer, the substrate height and dielectric constant as well as the loss tangent can be specified.

Parameters

Parameter	Discreption	Range of Usage
H1	Height of substrate layer 1 (H1= -1, –2 ® auto sizing)	4.n.DL (n=0,1,2,...)
H2	Height of substrate layer 2	n.DL(n=4,5,6,...)
H3	Height of substrate layer 3 (H3= -1, –2 ® auto sizing )	(4.n+ 3).DL (n=2,3,...)
ER1	Relative permittivity of layer 1	³ 1
ER2	Relative permittivity of layer 2	³ 1
ER3	Relative permittivity of layer 3	³ 1
TAND1	Dielectric loss factor of substrate layer 1	>0
TAND2	Dielectric loss factor of substrate layer 2	>0
TAND3	Dielectric loss factor of substrate layer 3	>0

Notes

As it is given above (Range of Usage), the parameter H1, H2 and H3 must be an integer multiple of DL (see DL in C_GRID for more information), so that the top and bottom electric walls as well as the dielectric layer boundaries lie on the grid. However, if the user specify a maximum deviation from grid (see ACC in C_GRID), the simulator can adapt the incompatible dimensions into the grid by changing these dimensions slightly (warnings will be reported). For ACC=0 (no deviation from grid) the simulator reports error and the next compatible value for the parameter will be suggested in the error message.
In case of coplanar lines and in order to keep the effects of upper and lower cover as small as possible, H1 and H3 should be as large as possible. The simulator adapts automatically the values for H₁and H₃ on the structure, if these parameters are set to –1 or –2 (auto sizing). A value of –1 for H1 and H3 is recommended.
If the user like to investigate the effects of upper or lower cover on structure characteristics, H₁ and H₃can be specified manually. For such applications, the minimum values for H₁ and H₃ and their compatibility to the grid (Range of Usage) have to be considered.
Set H₁=0 for the simulation of so called conductor-backed coplanar line (or to simulate the situation, when the substrate leis on metal during the on wafer measurements). The parameter H3 can be used or the simulation of packaging effects.
ER1, ER2 and ER3 can have any arbitrary value greater than or equal to 1. Set ER1 and ER3 to 1 (air) for the simulation of simple coplanar lines.
TAND1, TAND2 and TAND3 represents the dielectric loss factor of the three available layers. At the present, only the dielectric losses of the layer 2 (TAND2) is used for the simaulation whereas other two layers are assumed to be lossless.