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Coplanar Waveguide Substrate Definition: CPW_SUB

Symbol

Topology

Parameters

Name Description Unit Type Default
Er Relative dielectric constant   Er[1]
H Substrate thickness Length L[1]
T Conductor thickness Length T[1]
Rho Metal bulk resistivity normalized to gold   1
Tand Loss tangent of dielectric   Tand[1]
Hcover Cover height above substrate Length L[1]
Hab Air bridge height Length L[1]
Cover No cover if 0, else metallic cover at Hcover   L[1]
Gnd No ground plane if 0, else metallic ground plane backing   L[1]
Er_Nom Nominal dielectric constant   Er[1]
H_Nom Nominal substrate thickness Length L[1]
Hcov_Nom Nominal cover height Length L[1]
Hab_Nom Nominal air bridge height Length L[1]
T_Nom Nominal conductor thickness Length T
Name Substrate name Text CPW_SUB1[2]

[1] User-modifiable default. Modify by editing under $DEFAULT_VALUES in the default.lpf file in the root installation directory. See the AWR Microwave Office Layout Guide for details.

[2] Modify only if schematic contains multiple substrates. See “Using Elements With Model Blocks” for details.

Parameter Details

Er. Relative permittivity of dielectric constant of substrate material.

Rho. Rho is the bulk resistivity of conductor metal normalized to gold (to Rho_Gold=2.44 x 10 -8 Ω*m) Actual bulk resistivity of conductor metal is Rho*Rho_Gold Ω*m.

Hcover. Optional metallic cover elevation above the substrate. Valid only if parameter Cover is nonzero; not used otherwise.

Hab. Hab represents height of wire or strip air bridge that may be used to suppress an undesirable slotline (odd) mode.

Cover, Gnd. Cover and Gnd are unitless indicators; setting them to nonzero value (for example, 1) makes models that use this substrate to account for presence of metallic cover (element Cover) and/or ground plane (Gnd). Zero values of these indicators inform the model that corresponding item is not present.

Er_Nom. Er_Nom represents the nominal dielectric constant of the substrate relative to free space permittivity and is used only by the EM based models where all EM data is collected at Er_Nom and a variational approach is used to estimate the performance for small variations in Er about Er_Nom. See “How to Properly Set Up Substrate Parameters for X-models” for more details.

Hsub_Nom, Hcov_Nom, Hab_Nom, and T_Nom. These parameters are nominal values of corresponding parameters Er, Hsub, Hcover, Hab, and T; they are used only by the EM based models. See “How to Properly Set Up Substrate Parameters for X-models” for more details

Layout

This element does not have an assigned layout cell. You can assign artwork cells to any element. See “Assigning Artwork Cells to Layout of Schematic Elements” for details.

Recommendations for Use

CPW_SUB must be either present on the schematics that contain elements using CPW_SUB or it may be placed in the Global Definitions window. In the latter case, models using a global definition of CPW_SUB must refer to it explicitly.

Elements used with CPW_SUB

LINES OTHERS
CPW1LINE CPWABRGX
CPWALINE CPWEG
CPWLINE CPWGAP
CPWLINX CPWOC
CPWTAPER CPWSC

BEND JUNCTIONS COUPLED LINES
CPWBENDX CPWTEEX CPW2LINA
    CPW2LINE
    CPW3LINA

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