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U-turn (180-degrees) Stripline Bend: SUBEND

Symbol

Summary

SUBEND models an interconnect between the ends of two adjacent coupled stripline transmission lines. It comprises two right-angle non-mitered stripline bends connected with a transmission line. Its primary use is as a component of hairpin stripline filters.

SUBEND$ is the corresponding intelligent cell (iCell). An iCell model is identical to its non-iCell equivalent with the following exception: Certain dimension-related parameters are not explicitly user-specified; rather, they are automatically and dynamically determined by the dimensions of the attached elements. See the “Intelligent Cells (iCells)” for a detailed discussion of how to use iCells, their advantages, and their limitations.

Topology

Parameters

Name Description Unit Type Default
ID Name Text TL1
W Width of bends Length W[1]
S Gap between bends Length S[1]
M Bends miter (not used by this model) Scalar 0
SSUB Substrate definition Text SSUB#[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 the schematic contains multiple substrates. See the “Using Elements With Model Blocks” for details.

Parameter Details

M. Miter M is defined as D/X (see "Topology") and its value cannot exceed 0.5. Note that current version of SUBEND does not support non-zero values of M (bends are non-mitered) and model always assumes M=0.

Parameter Restrictions and Recommendations

  1. This model assumes that M=0 and ignores parameter M. However, the layout cell reflects changes in parameter M.

  2. Parameter W refers to both ports of SUBEND; SUBEND is intended to connect striplines of equal width.

Implementation Details

This model is implemented as a series connection of right-angle non-mitered stripline bend, stripline, and another right-angle non-mitered stripline bend.

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

This model is intended to provide a convenient mean for designing coupled line structures like hairpin filters. You can use it, however, with any type of striplines. The only limitation is a requirement of equal width of attached lines.

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