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(Obsolete) Microstrip Radial Stub Double Shunt (Closed Form): MDRSTUB



This element is OBSOLETE and is replaced by the Radial Stub, Double Shunt (Closed Form) (MDRSTUB2) element.



Name Description Unit Type Default
ID Element ID Text ST1
Ro Outer radius of the stub Length L[1]
W Conductor width Length W[1]
Wg Width of crossing of stub and microstrip line Length W[1]
Theta Angle of the stub Angle 90 Deg
MSUB Substrate definition Text MSUB#[2]

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

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

Implementation Details

This circuit component models a double-shunt "butterfly" radial stub on a single layer substrate (series stubs should be modeled with MRSTUB). Both stubs are of the same size.The model is a two port through element. The parameters W (width of the input microstrip), Wg (width of crossing of stub and microstrip line), and Ro (outer radius) are dimensions entered in the default length units. Theta is a radial stub angle entered in degrees. The parameter MSUB specifies the substrate element, which defines additional cross sectional parameters of the transmission line and substrate characteristics. If blank, a default is used. The model is valid up to its second open-circuit resonance and for 9 ≤ Theta ≤ 180.

The component accounts for losses in metal and in substrate dielectric. Dispersion is not included.


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.


[1] S.L. March, "Analyzing lossy radial-line stubs," IEEE Trans. Microwave Theory Tech., vol. MTT-33, March 1985, pp. 269-271

[2] F.Giannini, R.Ruggieri, and J.Vrba, "Shunt-connected microstrip radial stubs", IEEE Trans. Microwave Theory Tech., vol. MTT-34, March 1986, pp. 363-366

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