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# Coupler

Model ideal frequency-independent couplers with S-parameters

Junctions

## Description

Use the Coupler block to model four port directional couplers in a circuit envelope environment as an ideal S-parameter model.

## Dialog Box and Parameters

### Main Tab

Select component
• Directional coupler

The default option is Directional coupler. The s-parameter matrix for Directional coupler is:

$\left[\begin{array}{cccc}{r}_{l}& {i}_{l}& {i}_{s}& c\\ {i}_{l}& {r}_{l}& c& {i}_{s}\\ {i}_{s}& c& {r}_{l}& {i}_{l}\\ c& {i}_{s}& {i}_{l}& {r}_{l}\end{array}\right]$

where:

• rl = 10(-ReturnLoss/20)

• il = 10(-InsertionLoss/20)

• is = 10(-(Coupling+Directivity)/20)

• c = 10(-Coupling/20)

When you select this option, the following parameters are available:

• Coupling (dB)

Specify the coupling factor of Directional coupler. The valid value is nonnegative and real. The default value is 0 dB.

• Directivity (dB)

Specify the directivity of Directional coupler. The valid values are nonnegative and real. The default value is inf.

• Isolation (dB)

Specify the isolation of Directional coupler. The valid values are nonnegative and real. The default value is inf.

• Return loss (dB)

Specify the return loss of Directional coupler. The valid values are nonnegative and real. The default value is inf.

• Reference impedance (Ohm)

Specify the reference impedances of Directional coupler as scalar or three-tuple. The default values are 50 Ohms.

• Coupler symmetrical

The s-parameter matrix for Coupler symmetrical is:

$\left[\begin{array}{cccc}0& \alpha & 0& j\beta \\ \alpha & 0& j\beta & 0\\ 0& j\beta & 0& \alpha \\ j\beta & 0& \alpha & 0\end{array}\right]$

where:

• |α| ≤ 1 = Power transmission coefficient

• β = sqrt(1– α*α)

When you select this option, the following parameters are available:

• Power transmission coefficient

Specify the power transmission coefficient of Coupler symmetrical. The valid values are real. The default value is 0.

• Reference impedance (Ohm)

Specify the reference impedances of Coupler symmetrical as scalar or three-tuple. The default values are 50 Ohms.

• Coupler antisymmetrical

The s-parameter matrix for Coupler antisymmetrical is:

$\left[\begin{array}{cccc}0& \alpha & 0& \beta \\ \alpha & 0& -\beta & 0\\ 0& -\beta & 0& \alpha \\ \beta & 0& \alpha & 0\end{array}\right]$

where:

• |α| ≤ 1 = Power transmission coefficient.

• β = sqrt(1– α*α)

When you select this option, the following parameters are available:

• Power transmission coefficient

Specify the power transmission coefficient of Coupler antisymmetrical. The valid values are real. The default value is 0.

• Reference impedance (Ohm)

Specify the reference impedances of Coupler antisymmetrical as scalar or three-tuple. The default values are 50 Ohms.

• Hybrid quadrature (90deg)

The s-parameter matrix for Hybrid quadrature(90deg) is:

$\left[\begin{array}{cccc}0& -j/\sqrt{2}& 0& -1/\sqrt{2}\\ -j/\sqrt{2}& 0& -1/\sqrt{2}& 0\\ 0& -1/\sqrt{2}& 0& -j/\sqrt{2}\\ -1/\sqrt{2}& 0& -j/\sqrt{2}& 0\end{array}\right]\text{ }$

When you select this option, the following parameter is available:

• Reference impedance (Ohm)

Specify the reference impedances of Hybrid quadrature(90deg) as scalar or three-tuple. The default values are 50 Ohms.

• Hybrid rat-race

The s-parameter matrix for Hybrid rat-race is:

$\left[\begin{array}{cccc}0& -j/\sqrt{2}& 0& -j/\sqrt{2}\\ -j/\sqrt{2}& 0& j/\sqrt{2}& 0\\ 0& j/\sqrt{2}& 0& -j/\sqrt{2}\\ -j/\sqrt{2}& 0& -j/\sqrt{2}& 0\end{array}\right]\text{ }$

When you select this option, the following parameter is available:

• Reference impedance (Ohm)

Specify the reference impedances of Hybrid rat-race as scalar or three-tuple. The default values are 50 Ohms.

Ground and hide negative terminals

Select this option to internally ground and hide the negative terminals. Clear the option to expose the negative terminals. By exposing these terminals, you can connect them to other parts of your model.

By default, this option is selected.

## See Also

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