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Microstrip Substrate with Optional Cover Definition: MSUBC

Symbol

Topology

Parameters

Name Description Unit Type Default
Er Relative dielectric constant   Er[1]
H Substrate thickness Length H[1]
T Conductor thickness Length T[1]
Rho Metal bulk resistivity normalized to gold   Rho[1]
Tand Loss tangent of dielectric   0
ErNom[2] Nominal relative dielectric constant (used by X-models only)   Er[1]
Cover Switch "Metallic Cover" / "No Cover"/"Metallic Box"   "No Cover"
ErC Relative dielectric constants of layer adjacent to cover   1
TandC Loss tangent of layer adjacent to cover   0
HC Cover height over the substrate Length H[1]
SW Separation of vertical metallic walls from extreme left/right conductors (used only by box option) Length L[1]
Name Substrate name Text MSUBC1[3]

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

[2] See “X-model Tables Shipped with the AWR Design Environment” for a list of available X-model tables.

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

Implementation Details

Er.Er is the permittivity of the substrate material relative to the permittivity of free space ε0 = 8.854*10-12 F/M

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

Tand.Tand is the dielectric loss tangent of the substrate material: Tand = εr″/εr′ where εr = εr′ -jεr

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

H and T.H and T are cross-sectional dimensional variables given in default length units.

ErC. If switch Cover is set to "Metallic Cover" or "Metallic Box" this parameter specifies relative dielectric constant of a layer that adjoins the cover. If switch Cover is set to "No Cover" parameter ErC is not used.

TandC. If switch Cover is set to "Metallic Cover" or "Metallic Box" this parameter specifies loss tangent of a layer that adjoins the cover. If switch Cover is set to "No Cover" parameter TandC is not used.

HC. Specification of height over the substrate HC is mandatory if switch Cover is set to "Metallic Cover" or "Metallic Box" . If switch Cover is set to "No Cover" parameter HC is not used.

SW. Distance from the left-most/right-most conductor to the left/right wall. The SW parameter is used only if the Cover parameter is set to "Metallic Box."

Cover. This switch can be set to one of three selections: "Metallic Cover", "No Cover", "Metallic Box." "Metallic Cover" provides a covered structure typical for striplines; Parameters HC, ErC, TandC are used, SW is not used. "No Cover" provides an open structure typical for microstrips; Parameters HC, ErC, TandC, and SW are not used. Selection "Metallic Box" installs metallic cover and adds side metallic walls thus confining the whole structure into rectangular metallic enclosure; Parameter SW is used.

In a schematic that contains microstrip elements, at least one instance of this element must exist. The Name parameter provides a unique identifier for each instance of MSUBC. The microstrip elements have an MSUBC parameter that indicates which MSUBC element to use.

Note that you can also add this substrate to the Global Definitions window and then reference the material from any schematic.

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.

Elements Used with MSUBC

COMPONENTS COUPLED LINES INTERCONNECTS
MRINDSBC MNCLIN WIRE1C
MRINDNBC    
MLANGE2C    
MCAPC    
MCAP1C    
MCAP2C    

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