Coupler

Model ideal frequency-independent couplers with S-parameters

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  • Library:

  • RF Blockset / Circuit Envelope / Junctions

  • Coupler block

Description

The Coupler block models four port directional couplers in a circuit envelope environment as an ideal S-parameter model. The four ports of the coupler are Input port (Port 1), Through port (Port 2), Isolated port (Port 3), Coupled port (Port 4).

Directional couplers are used to sample forward and reflected waves propagating along a transmission line. Directional couplers find uses in many RF design applications such as line power sensors and transmitter automatic level controls.

Hybrid couplers are used to split or combine signals with specific phase relations.

Parameters

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Coupler type, specified as:

  • Directional coupler

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

    [rliliscilrlcisiscrlilcisilrl]

    where:

    • rl = 10(-ReturnLoss/20)

    • il = j10(-InsertionLoss/20)

    • is = j10(-(Coupling+Directivity)/20)

    • c = 10(-Coupling/20)

    Note

    In release 2019a, the s-parameter representation of the Directional Coupler block is altered to permit a valid implementation for all specified mask values. This implementation adds a 90 degree phase shift to s12, s13, s21, s24, s31, s34, s42, and s43 terms. In addition, a -180 phase shift is added to the s14, s23, s32 and s41 terms.

    Use this option to model coupler parameters from data sheets.

  • Coupler symmetrical

    The s-parameter matrix for Coupler symmetrical is:

    [0α0jβα0jβ00jβ0αjβ0α0]

    where:

    • |α| ≤ 1 = Power transmission coefficient

    • β = sqrt(1– α*α)

  • Coupler antisymmetrical

    The s-parameter matrix for Coupler antisymmetrical is:

    [0α0βα0−β00−β0αβ0α0]

    where:

    • |α| ≤ 1 = Power transmission coefficient.

    • β = sqrt (1– α*α)

  • Hybrid quadrature (90deg)

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

    [0-j/20-1/2-j/20-1/200-1/20-j/2-1/20-j/20] 

  • Hybrid rat-race

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

    [0−j/20−j/2−j/20j/200j/20−j/2−j/20−j/20] 

  • Magic tee

    The s-parameter matrix for the Magic tee is:

    [0011001−111001−100]2

Fraction of input signal power coupled to output port of the Directional coupler, specified as a nonnegative and real scalar. The default value is 0 dB.

Dependencies

To enable this parameter, select Directional coupler in Select component tab.

Ratio of power at coupled port to power at isolated port of the Directional coupler, specified as a nonnegative and real scalar. The default value is inf.

Dependencies

To enable this parameter, select Directional coupler in Select component tab.

Loss of signal power between input and output ports of the Directional coupler, specified as a nonnegative and real scalar. The default value is inf.

Dependencies

To enable this parameter, select Directional coupler in Select component tab.

Loss of signal power due to impedance mismatch of the Directional coupler, specified as a nonnegative, and real scalar. The default value is inf.

Dependencies

To enable this parameter, select Directional coupler in Select component tab.

Transmitted signal power of the Directional coupler, specified as a real scalar. The default value is 0.

Dependencies

To enable this parameter, select Coupler symmetrical or Coupler antisymmetrical in Select component tab.

Reference impedance of coupler, specified as a scalar or three-tuple. The default value is 50 Ohms.

Select this parameter to ground and hide the negative terminals. To expose the negative terminals, clear this parameter. 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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Introduced in R2014a

RF Blockset Documentation

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