# designUncoupledLine

Calculate dimensions of uncoupled-line section for specified frequency

Since R2022a

## Syntax

``[Length,Width] = designUncoupledLine(balunobj,frequency)``
``___ = designUncoupledLine(___,Name=Value)``

## Description

````[Length,Width] = designUncoupledLine(balunobj,frequency)` calculates the dimensions of the uncoupled-line section of a coupled line balun around a specified frequency. In the `balunCoupledLine` object, the uncoupled line dimensions are incorporated into the UncoupledLineShape property. Note`designUncoupledLine` is the second step in designing a coupled line balun. This function is preceded by `designCoupledLine` and succeeded by `designOutputLine`. ```

example

````___ = designUncoupledLine(___,Name=Value)` calculates the dimensions of the uncoupled-line section of a coupled-line balun with additional options specified using name-value arguments. NotePCB components designed using the `design` function operate around the specified frequency with a 10-15% tolerance. ```

## Examples

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Define the frequency at 4 GHz.

`f = 4e9;`

Create a coupled line balun object.

`balun = balunCoupledLine`
```balun = balunCoupledLine with properties: NumCoupledLineSection: 3 CoupledLineLength: 0.0153 CoupledLineWidth: 4.0000e-04 CoupledLineSpacing: 1.4000e-04 UncoupledLineShape: [1×1 ubendMitered] OutputLineLength: 0.0124 OutputLineWidth: 1.5300e-04 OutputLineSpacing: 0.0110 Height: 0.0013 GroundPlaneWidth: 0.0200 Substrate: [1×1 dielectric] Conductor: [1×1 metal] ```
`show(balun)`

Step 1: Design coupled line section

Design the coupled line section of the balun with an even mode impedance of 159 ohms and an odd mode impedance of 51 ohms. Use the helper function designCoupledLine.

`[ClineL,ClineW,ClineS] = designCoupledLine(balun,f,'Z0e',159,'Z0o',51)`
```ClineL = 0.0107 ```
```ClineW = 4.2682e-04 ```
```ClineS = 1.4374e-04 ```

Step 2: Design uncoupled line section

Design the uncoupled line section of the balun with the even and odd mode impedance of 59 ohms. Use the helper function designUncoupledLine.

`[unclineL,unclineW] = designUncoupledLine(balun,f,'Z0',59,'LineLength',0.25)`
```unclineL = 0.0103 ```
```unclineW = 0.0018 ```

Step 3: Design output line section

Design the output line section of the balun at the same frequency to extend the port 2 and port3. Use the helper function designOutputLine.

`[OutL,OutW] = designOutputLine(balun,f,'Z0e',159,'Z0o',51,'Z0',59,'Zref',50)`
```OutL = 0.0109 ```
```OutW = 1.6115e-04 ```

Set all the design dimensions to the coupled balun object.

```balun.CoupledLineLength = ClineL; balun.CoupledLineWidth = ClineW; balun.CoupledLineSpacing = ClineS; UnCoupledLine = ubendMitered; UnCoupledLine.Length = [unclineL/2,unclineL/4,unclineL/2]; UnCoupledLine.Width = [unclineW,unclineW,unclineW]; balun.UncoupledLineShape = UnCoupledLine; balun.OutputLineLength = OutL; balun.OutputLineWidth = OutW; balun.OutputLineSpacing = OutL+ClineS; gndW = 25e-3; balun.GroundPlaneWidth = gndW; show(balun)```

Analyze and plot the S-parameters of this balun.

```s11 = sparameters(balun,linspace(3.5e9,4.5e9,31)); figure; rfplot(s11,1,1); hold on; rfplot(s11,1,3) hold on; rfplot(s11,1,2)```

## Input Arguments

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Coupled-line balun, specified as a `balunCoupledLine` object.

Example: ```balunobj = balunCoupledLine; design(balunobj,2e9)``` designs a coupled-line balun around a frequency of 2 GHz and returns the length and width of the uncoupled line section.

Design frequency of coupled-line balun, specified as a real positive scalar in hertz.

Example: `55e6`

Data Types: `double`

### Name-Value Arguments

Example: `Z0=60`

Impedance of uncoupled-line, specified as a positive scalar in ohms.

Data Types: `double`

Length of uncoupled-line specified as a positive scalar in multiples of lambda. In the `balunCoupledLine` object, the uncoupled line dimensions are incorporated into the UncoupledLineShape property. `UncoupledLineShape.Length` is the vector of size `3` and the `LineLength` property should be splitted accordingly.

Data Types: `double`

## Output Arguments

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Length of the uncoupled-line section, returned as a positive scalar.

Width of the uncoupled-line section, returned as a positive scalar.

## Version History

Introduced in R2022a