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Microstrip Transmission Line

Model microstrip transmission line

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  • RF Blockset / Equivalent Baseband / Transmission Lines

  • Microstrip Transmission Line block

Description

The Microstrip Transmission Line block models the microstrip transmission line described in the block dialog in terms of its frequency-dependent S-parameters. A microstrip transmission line is shown in cross-section in the following figure. Its physical characteristics include the microstrip width (w), the microstrip thickness (t), the substrate height (d), and the relative permittivity constant (ε).

Cross-section of microstrip transmission line

Parameters

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Main

Width of the microstrip transmission line, specified as a scalar in meters.

Thickness of the dielectric on which the conductor resides in the coplanar waveguide, specified as a scalar in meters.

Physical thickness of the conductor in which wave propagates, specified as a positive scalar in meters.

Relative permittivity of the dielectric expressed as the ratio of the permittivity of the dielectric to permittivity in free space ε0, specified as a scalar.

Loss tangent of the dielectric, specified as a scalar.

Conductivity of the conductor, specified as a positive scalar in Siemens/meters. Conductivity measures the ease with which current flows in the conductor.

Physical length of the transmission line, specified as a positive scalar in meters.

The block enables you to model the transmission line as a stub or as a stubless line.

Stubless Transmission Line

  • Not a stubNot a stub

    If you model a coaxial transmission line as stubless line, the Coaxial Transmission Line block first calculates the ABCD-parameters at each frequency contained in the modeling frequencies vector. It then uses the abcd2s function to convert the ABCD-parameters to S-parameters. For more information, see Stub Mode - Not a Stub.

Shunt Transmission Line

  • Shunt—This parameter provides a two-port network that consists of a stub transmission line that you can terminate with either a short circuit or an open circuit as shown in these diagrams.

    Shunt transmission line

    Zin is the input impedance of the shunt circuit. The ABCD-parameters for the shunt stub are calculated as

    A=1B=0C=1/ZinD=1

Series Transmission Line

  • Series—This mode parameter provides a two-port network that consists of a series transmission line that you can terminate with either a short circuit or an open circuit as show in these diagrams.

    Series transmission line

    Zin is the input impedance of the series circuit. The ABCD-parameters for the series stub are calculated as

    A=1B=ZinC=0D=1

Stub termination for stub modes Shunt and Series. Choices are Open or Short

Dependencies

To enable this parameter, select Shunt or Series in Stub mode

Stub termination for stub modes Shunt and Series. Choices are Open or Short

Dependencies

To enable this parameter, select Shunt, or Series, or in Stub mode

Visualization

Frequency data source, specified as User-specified.

Frequency data range, specified as a vector in hertz.

Reference impedance, specified as a nonnegative scalar in ohms.

Type of data plot to visualize using the given data, specified as one of the following:

  • X-Y plane — Generate a Cartesian plot of the data versus frequency. To create linear, semilog, or log-log plots, set the Y-axis scale and X-axis scale accordingly.

  • Composite data — Plot the composite data. For more information, see Create Plots.

  • Polar plane — Generate a polar plot of the data. The block plots only the range of data corresponding to the specified frequencies.

  • Z smith chart, Y smith chart, and ZY smith chart — Generate a Smith® chart. The block plots only the range of data corresponding to the specified frequencies.

Type of parameters to plot, specified as one of the following.

S11S12S21S22
GroupDelayGammaInGammaOutVSWRIn
VSWROutOIP3IIP3NF
NFactorNTempTF1TF2
TF3GtGaGp
GmagGmsgGammaMSGammaML
KDeltaMuMuPrime

Note

Y parameter1 is disabled when you select Plot type to Composite data.

Type of parameters to plot, specified as one of the following.

S11S12S21S22
GroupDelayGammaInGammaOutVSWRIn
VSWROutOIP3IIP3NF
NFactorNTempTF1TF2
TF3GtGaGp
GmagGmsgGammaMSGammaML
KDeltaMuMuPrime

Note

Y parameter2 is disabled when you select Plot type to Composite data.

Plot format, specified as one of the following.

Y parameter1Y format1
S11, S12, S21, S22, GammaIn, GammaOut, TF1, TF2, TF3, GammaMS, GammaML, and Delta.dB, Magnitude (decibels), Abs, Mag, Magnitude (linear), Angle, Angle(degrees), Angle(radians), Real, Imag, and Imaginary.
GroupDelayns, us, ms, s, and ps.
VSWRIn and VSWROut.Magnitude (decibels) and None.
OIP3 and IIP3.dBm, W, and mW.
NF dB and Magnitude (decibels).
NFactor, K, Mu, and MuPrime.None
NTempKelvin
Gt, Ga, Gp, Gmag, and Gmsg.dB, Magnitude (decibels), and None.

Dependencies

To enable Y format1, set Plot type to X-Y plane.

Plot format, specified as one of the following.

Y parameter2Y format2
S11, S12, S21, S22, GammaIn, GammaOut, TF1, TF2, TF3, GammaMS, GammaML, and Delta.dB, Magnitude (decibels), Abs, Mag, Magnitude (linear), Angle, Angle(degrees), Angle(radians), Real, Imag, and Imaginary.
GroupDelayns, us, ms, s, and ps.
VSWRIn and VSWROut.Magnitude (decibels) and None.
OIP3 and IIP3.dBm, W, and mW.
NF dB and Magnitude (decibels).
NFactor, K, Mu, and MuPrime.None
NTempKelvin
Gt, Ga, Gp, Gmag, and Gmsg.dB, Magnitude (decibels), and None.

Dependencies

To enable Y format2, set Plot type to X-Y plane.

Frequency plot, specified as Freq.

Frequency plot format, specified as one of the following.

AutoHzkHzMHz
GHzTHz  

Y-axis scale, specified as Linear or Log.

Dependencies

To enable this parameter, set Plot type to X-Y plane.

X-axis scale, specified as Linear or Log.

Dependencies

To enable this parameter, set Plot type to X-Y plane.

Plot the specified data using the plot button.

More About

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References

[1] Gupta, K.C., G. Ramesh, I. Bahl, and P. Bhartia. Microstrip Lines and Slotlines, Second Edition. Artech House, 1996. pp. 102-109.

Introduced in R2009a