S-Parameters

Model S-parameter network

Library:
RF Blockset / Circuit Envelope / Elements

Description

The S-parameters block models a network defined by S-parameters in the RF Blockset™ circuit envelope simulation environment. The device can have up to 32 ports. For an introduction to RF simulation, see the example, Simulate High Frequency Components.

The block models S-parameter data in the RF Blockset environment by fitting a rational function to the specified data. For more information about rational fitting of S-parameters, see the RF Toolbox™ rationalfit function.

Note

If you specify more than eight ports, the block does not simulate noise.

Parameters

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Main

`Data source` — Data source
`Data file` (default) | `Network-parameters` | `Rational model`

Data source for S-parameters behavior, specified as one of the following:

Data file — Name of a Touchstone file with the extension.s2p. The block ignores noise and nonlinearity data in imported files.
Network-parameters — Provide Network parameter data such as S-parameters, Y-parameters, and Z-parameters with corresponding Frequency and Reference impedance (ohms) for the s-parameters.
Rational model — Provide values for Residues, Poles, and Direct feedthrough parameters which correspond to the equation for a rational model

$F (s) = (\sum_{k = 1}^{n} \frac{C_{k}}{s - A_{k}} + D) \begin{matrix} , & s = j 2 π f \end{matrix}$
.In this rational model equation, each C_k is the residue of the pole A_k. If C_k is complex, a corresponding complex conjugate pole and residue must also be enumerated. This object has the properties C, A, and D. You can use these properties to specify the Residues, Poles, and Direct feedthrough parameters.

`Data file` — Name of network parameter data file
`simrfV2_unitygain.s2p` (default) | character vector

Name of network parameter data file, specified as a character vector.

Dependencies

To enable this parameter, select Data file in Data source tab.

`Network parameter type` — Network parameter type
`S-parameters` (default) | `Y-parameters` | `Z-parameters`

Network parameter type, specified as S-parameters, Y-parameters, or Z-parameters.

Dependencies

To enable this parameter, select Network-parameters in Data source tab.

`Network-parameters` — Network parameter values
`[0 0;1 0]` (default) | multidimensional array

Network parameter values specified as a multidimensional array. The third dimension of the S-parameter array must be the same length as the vector of frequencies specified by the Frequency parameter. The default values are different for S-parameters, Y-parameters, and Z-parameters respectively.

Dependencies

To enable this parameter, select Network-parameters in Data source tab.

`Frequency (dB)` — Frequency of network parameters
`1e9 Hz` (default) | scalar | vector | `Hz` | `kHz` | `MHz` | `GHz`

Frequency of network parameters, specified as a scalar or a vector in Hz.

Dependencies

To enable this parameter, select Network-parameters in Data source.

`Reference Impedance(Ohm)` — Reference impedance of network parameters
`50` (default) | scalar

Reference impedance of network parameters, specified as a scalar.

Dependencies

To enable this parameter, select Network-parameters in Data source tab.

`Residues` — Residues in order of rational model
`0` (default) | vector

Residues in order of rational model, specified as a vector.

Dependencies

To enable this parameter, select Rational model in Data source tab.

`Poles` — Residues in order of rational model
`0` (default) | vector

Poles in order of rational model, specified as a vector.

Dependencies

To enable this parameter, select Rational model in Data source tab.

`Direct feedthrough` — Direct feedthrough
`{0 0:1 0}` (default) | array of vectors

Direct feedthrough, specified as an array vector.

Dependencies

To enable this parameter, select Rational model in Data source tab. .

`Simulate noise` — Generate thermal noise waves
`off` (default) | `on`

Choose this parameter to generate thermal noise waves [1]. Clear this parameter to stop simulating noise. For more information see, Generate Thermal Noise.

Note

This parameter is disabled when you specify more than eight ports.

`Ground and hide negative terminals` — Ground RF circuit terminals
`on` (default) | `off`

Select this parameter to ground and hide the negative terminals. Clear this parameter 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.

Modeling

`Modeling options` — Model S-parameters
`Time-domain (rationalfit)` (default) | `Frequency-domain`

Model S-parameters, specified as:

Time-domain (rationalfit) technique creates an analytical rational model that approximates the whole range of the data. When modeling using Time domain, the Plot in Visualization tab plots the data defined in Data Source and the values in the rationalfit function.
Frequency-domain computes the baseband impulse response for each carrier frequency independently. This technique is based on convolution. There is an option to specify the duration of the impulse response. For more information, see Compare Time and Frequency Domain Simulation Options for S-parameters.
For the Amplifier and S-parameters blocks, the default value is Time domain (rationalfit). For the Transmission Line block, the default value is Frequency domain.

Dependencies

To set this parameter, first select Data file or Network-parameters in Data source. This selection activates the Visualization Tab which contains Source of frequency data

`Fitting options` — Rationalfit fitting options
`Fit individually` (default) | `Share poles by column` | `Share all poles`

Rationalfit fitting options, specified as Fit individually, Share poles by column, or Share all poles.

Rational fitting results shows values of Number of independent fits, Number of required poles, and Relative error achieved (dB).

Dependencies

To set this parameter, select Time domain (rationalfit) in Modeling options.

`Relative error desired (dB)` — Relative error acceptable for the rational fit
`-40` (default) | scalar

Relative error acceptable for the rational fit, specified as a scalar.

Dependencies

To set this parameter, select Time domain (rationalfit) in Modeling options.

`Automatically estimate impulse response duration` — Automatically calculate impulse response
`on` | `off`

Select this parameter to automatically calculate impulse response. Clear this parameter to manually specify the impulse response duration using Impulse response duration.

Dependencies

To set this parameter, select Frequency domain in Modeling options.

`Impulse response duration` — Impulse response duration
`1e-10` (default) | scalar

Impulse response duration, specified as a scalar.

Dependencies

To set this parameter, first select Frequency domain in Modeling options. Then, clear Automatically estimate impulse response duration.

`Use only S-parameter magnitude with appropriate delay` — Use only S-parameter magnitude with appropriate delay
`off` (default) | `on`

Select this parameter to ignore the s-parameter phase and delay the impulse response by half its length. This parameter is applicable only for S-parameter data modeled in time domain. You can use this to shape spectral content with filter effects by specifying only magnitude.

Note

This parameter introduces an artificial delay to the system.

Visualization

`Source of frequency data` — Frequency data source
`Extracted from data source` (default) | `User-defined`

Frequency data source, specified as:

When Source of frequency data is Extracted from data source, the Data source must be set to Data file. Verify that the specified Data file contains frequency data.

When Source of frequency data is User-specified, specify a vector of frequencies in the Frequency data parameter. Also, specify units from the corresponding drop-down list.

`Frequency data` — Frequency data range
`[1e9:1e6:3e9]` (default) | vector | `Hz` | `kHz` | `MHz` | `GHz`

Frequency data range, specified as a vector

`Plot type` — Type of data plot
`X-Y plane` (default) | `Polar plane` | `Z Smith chart` | `Y Smith chart` | `ZY Smith chart`

Type of data plot that you want to produce with your data specified as one of the following:

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

`Parameter 1` — Type of S-Parameters to plot
`S11` (default) | `SNN`

Type of S-Parameters to plot, specified as SNN, where N is the number of ports in the s-parameters block.

`Parameter 2` — Type of S-Parameters to plot
`None` (default) | `SNN`

Type of S-Parameters to plot, specified as SNN, where N is the number of ports in the s-parameters block.

`Format1` — Plot format
`Magnitude (decibels)` (default) | `Angle(degrees)` | `Real` | `Imaginary`

Plot format, specified as Magnitude (decibels), Angle(degrees), Real, or Imaginary.

`Format2` — Plot format
`Magnitude (decibels)` (default) | `Angle(degrees)` | `Real` | `Imaginary`

Plot format, specified as Magnitude (decibels), Angle(degrees), Real, or Imaginary.

`Y-axis scale` — Y-axis scale
`Linear` (default) | `Logarithmic`

Y-axis scale, specified as Linear or Logarithmic.

`X-axis scale` — X-axis scale
`Linear` (default) | `Logarithmic`

X-axis scale, specified as Linear or Logarithmic.

`Plot` — Plot specified data
button

Plot specified data using plot button.

Model Examples

Architectural Design of a Low IF Receiver System

Use the RF Blockset™ Circuit Envelope library to simulate the performance of a Low IF architecture with the following RF impairments: Component noise

Compare Time and Frequency Domain Simulation Options for S-parameters

Use two different options for modeling S-parameters with the RF Blockset™ Circuit Envelope library. The Time-domain (rationalfit) technique creates an analytical rational model that approximates the whole range of the data. This is a preferable technique when a good fit could be achieved with a small number of poles. When the data has a lot of details or high level of noise, this model becomes large and slow to simulate.

More About

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Generate Thermal Noise

You can only generate thermal noise if the given S-parameters multiport components are passive.

To include the noise waves, the block augments the S-parameters equation:

$b = S a + c$

a and b — Customary wave vectors
c — Noise wave vector

The noise wave vector, noise correlation matrix, and S-parameters have these relationships:

$C_{s} = K * T (I - S S^{†}) = \bar{c c^{†}}$

where:

K — Boltzmann's constant
T — System temperature
c — Noise wave vector

References

[1] Wedge, Scott & Rutledge, David. " Wave Techniques for Noise Modeling and Measurement" IEEE Transactions on Microwave Theory and Techniques. Vol. 40, Number 11, pp. 2004–2012, Nov. 1992.

Documentation

S-Parameters

Description

Parameters

Data source — Data source Data file (default) | Network-parameters | Rational model

Data file — Name of network parameter data file simrfV2_unitygain.s2p (default) | character vector

Dependencies

Network parameter type — Network parameter type S-parameters (default) | Y-parameters | Z-parameters

Dependencies

Network-parameters — Network parameter values [0 0;1 0] (default) | multidimensional array

Dependencies

Frequency (dB) — Frequency of network parameters 1e9 Hz (default) | scalar | vector | Hz | kHz | MHz | GHz

Dependencies

Reference Impedance(Ohm) — Reference impedance of network parameters 50 (default) | scalar

Dependencies

Residues — Residues in order of rational model 0 (default) | vector

Dependencies

Poles — Residues in order of rational model 0 (default) | vector

Dependencies

Direct feedthrough — Direct feedthrough {0 0:1 0} (default) | array of vectors

Dependencies

Simulate noise — Generate thermal noise waves off (default) | on

Ground and hide negative terminals — Ground RF circuit terminals on (default) | off

Modeling options — Model S-parameters Time-domain (rationalfit) (default) | Frequency-domain

Dependencies

Fitting options — Rationalfit fitting options Fit individually (default) | Share poles by column | Share all poles

Dependencies

Relative error desired (dB) — Relative error acceptable for the rational fit -40 (default) | scalar

Dependencies

Automatically estimate impulse response duration — Automatically calculate impulse response on | off

Dependencies

Impulse response duration — Impulse response duration 1e-10 (default) | scalar

Dependencies

Use only S-parameter magnitude with appropriate delay — Use only S-parameter magnitude with appropriate delay off (default) | on

Source of frequency data — Frequency data source Extracted from data source (default) | User-defined

Frequency data — Frequency data range [1e9:1e6:3e9] (default) | vector | Hz | kHz | MHz | GHz

Plot type — Type of data plot X-Y plane (default) | Polar plane | Z Smith chart | Y Smith chart | ZY Smith chart

Parameter 1 — Type of S-Parameters to plot S11 (default) | SNN

Parameter 2 — Type of S-Parameters to plot None (default) | SNN

Format1 — Plot format Magnitude (decibels) (default) | Angle(degrees) | Real | Imaginary

Format2 — Plot format Magnitude (decibels) (default) | Angle(degrees) | Real | Imaginary

Y-axis scale — Y-axis scale Linear (default) | Logarithmic

X-axis scale — X-axis scale Linear (default) | Logarithmic

Plot — Plot specified data button

Model Examples

Architectural Design of a Low IF Receiver System

Compare Time and Frequency Domain Simulation Options for S-parameters

More About

Generate Thermal Noise

References

See Also

RF Blockset Documentation

Support

`Data source` — Data source
`Data file` (default) | `Network-parameters` | `Rational model`

`Data file` — Name of network parameter data file
`simrfV2_unitygain.s2p` (default) | character vector

`Network parameter type` — Network parameter type
`S-parameters` (default) | `Y-parameters` | `Z-parameters`

`Network-parameters` — Network parameter values
`[0 0;1 0]` (default) | multidimensional array

`Frequency (dB)` — Frequency of network parameters
`1e9 Hz` (default) | scalar | vector | `Hz` | `kHz` | `MHz` | `GHz`

`Reference Impedance(Ohm)` — Reference impedance of network parameters
`50` (default) | scalar

`Residues` — Residues in order of rational model
`0` (default) | vector

`Poles` — Residues in order of rational model
`0` (default) | vector

`Direct feedthrough` — Direct feedthrough
`{0 0:1 0}` (default) | array of vectors

`Simulate noise` — Generate thermal noise waves
`off` (default) | `on`

`Ground and hide negative terminals` — Ground RF circuit terminals
`on` (default) | `off`

`Modeling options` — Model S-parameters
`Time-domain (rationalfit)` (default) | `Frequency-domain`

`Fitting options` — Rationalfit fitting options
`Fit individually` (default) | `Share poles by column` | `Share all poles`

`Relative error desired (dB)` — Relative error acceptable for the rational fit
`-40` (default) | scalar

`Automatically estimate impulse response duration` — Automatically calculate impulse response
`on` | `off`

`Impulse response duration` — Impulse response duration
`1e-10` (default) | scalar

`Use only S-parameter magnitude with appropriate delay` — Use only S-parameter magnitude with appropriate delay
`off` (default) | `on`

`Source of frequency data` — Frequency data source
`Extracted from data source` (default) | `User-defined`

`Frequency data` — Frequency data range
`[1e9:1e6:3e9]` (default) | vector | `Hz` | `kHz` | `MHz` | `GHz`

`Plot type` — Type of data plot
`X-Y plane` (default) | `Polar plane` | `Z Smith chart` | `Y Smith chart` | `ZY Smith chart`

`Parameter 1` — Type of S-Parameters to plot
`S11` (default) | `SNN`

`Parameter 2` — Type of S-Parameters to plot
`None` (default) | `SNN`

`Format1` — Plot format
`Magnitude (decibels)` (default) | `Angle(degrees)` | `Real` | `Imaginary`

`Format2` — Plot format
`Magnitude (decibels)` (default) | `Angle(degrees)` | `Real` | `Imaginary`

`Y-axis scale` — Y-axis scale
`Linear` (default) | `Logarithmic`

`X-axis scale` — X-axis scale
`Linear` (default) | `Logarithmic`

`Plot` — Plot specified data
button