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Microstrip Radial Stub Series (Closed Form): MRSTUB2W

Symbol

Summary

MRSTUB2W models a microstrip radial stub that terminates a microstrip line. The stub is connected to a single node at the reference plane.

Topology

Parameters

Name Description Unit Type Default
ID Element ID Text ST1
W Width of connecting microstrip line Length L[1]
Ro Outer radius of the stub Length L[1]
Theta Angle of the stub Angle 90 Deg
MSUB Substrate definition Text MSUB1[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

W. The conductor width of the connecting microstrip line. If needed, the inner radius Ri can be easily obtained from the specified microstrip width W and the stub angle Theta:

Parameter Restrictions and Recommendations

  1. Theta must be within the range 9 ≤ Theta ≤ 160 .

  2. This model is feasible if (Ro-Ri)/Ro > 0.01 .

Implementation Details

Model implementation is based on cascading multiple segments of lossy microstrip transmission lines described in [1]. It accounts for losses in metal and in substrate dielectrics. Radiation loss is not included.

Layout

This element uses line types to determine its layout. By default, the layout uses the first line type defined in your Layout Process File (LPF). You can change the element to use any of the line types configured in your process:

  1. Select the item in the layout.

  2. Right-click and choose Shape Properties to display the Cell Options dialog box.

  3. Click the Layout tab and select a Line Type.

  4. Click OK to use the new line type in the layout.

See “Cell Options Dialog Box: Layout Tab ” for Cell Options dialog box Layout tab details.

See “The Layout Process File (LPF)” for more information on editing Layout Process Files (LPFs) and to learn about adding or editing line types.

Recommendations for Use

MRSTUB2W replaces the MRSTUB element, which is obsolete. MRSTUB2W is also recommended for use instead of MRSTUB2 because MRSTUB2W is easily accessible for measuring the W parameter, while MRSTUB2 relies on the less convenient internal radius Ri.

Discontinuity models function most accurately when attached to lines that match their corresponding edges. Directly connecting discontinuity models to one another reduces their accuracy.

References

[1] B.C.Wadell, Transmission Line Design Book, Artech House, Boston-London, 1991, pp.306-307

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