Note: This page has been translated by MathWorks. Please click here

To view all translated materals including this page, select Japan from the country navigator on the bottom of this page.

To view all translated materals including this page, select Japan from the country navigator on the bottom of this page.

Model passive network using Z-parameters

Black Box Elements sublibrary of the Physical library

The Z-Parameters Passive Network block models the two-port passive network described in the block dialog box, in terms of its Z-parameters and their associated frequencies.

In the **Z-Parameters** field of the block
dialog box, provide the Z-parameters for each of M frequencies as
a 2-by-2-by-M array. In the **Frequency** field,
specify the frequencies for the Z-parameters as an M-element vector.
The elements of the vector must be in the same order as the Z-parameters.
All frequencies must be positive. For example, the following figure
shows the correspondence between the Z-parameters array and the vector
of frequencies.

The Z-Parameters Passive Network block uses the RF Toolbox™ `z2s`

function to convert the Z-parameters to
S-parameters, and then interpolates the resulting S-parameters to
determine their values at the modeling frequencies. The modeling frequencies
are determined by the Output Port block. See RF Blockset Equivalent Baseband Algorithms for
more details.

**Z-Parameters**Z-parameters for a two-port passive network in a 2-by-2-by-M array. M is the number of Z-parameters.

**Frequency (Hz)**Frequencies of the Z-parameters as an M-element vector. The order of the frequencies must correspond to the order of the Z-parameters in

**Z-Parameters**. All frequencies must be positive.**Interpolation method**The method used to interpolate the network parameters. The following table lists the available methods describes each one.

Method Description `Linear`

(default)Linear interpolation `Spline`

Cubic spline interpolation `Cubic`

Piecewise cubic Hermite interpolation

For information about plotting, see Create Plots.

The following example specifies Z-parameters [0.13 - 5.93i,
.03-3.16i; 0.03-3.16i, .13-5.93i] and [0.27-2.86i, -.09-5.41i; -.09-5.41i,
.27-2.86i] at frequencies 2.0 GHz and 2.1 GHz respectively. It uses
the MATLAB^{®} `cat`

function
to create the 2-by-2-by-2 Z-parameters array.

cat(3,[0.13-5.93i, .03-3.16i; 0.03-3.16i, .13-5.93i],... [0.27-2.86i,-.09-5.41i; -.09-5.41i, .27-2.86i])

Type the following command at the MATLAB prompt to create a variable called

`zparams`

that stores the values of the Z-parameters.zparams = cat(3,... [0.13-5.93i,.03-3.16i; 0.03-3.16i,.13-5.93i],... [0.27-2.86i,-.09-5.41i; -.09-5.41i,.27-2.86i])

Set the Z-Parameters Passive Network block parameters on the

**Main**tab as follows:Set the

**Z-Parameters**parameter to`zparams`

.Set the

**Frequency (Hz)**parameter to`[2.0e9,2.1e9]`

.

Click

**Apply**. This action applies the specified settings.Set the Z-Parameters Passive Network block parameters on the

**Visualization**tab as follows:In the

**Source of frequency data**list, select`User-specified`

.Set the

**Frequency data (Hz)**parameter to`[1.9e9:1.0e8:2.2e9]`

.In the

**Y parameter1**list, select`S12`

.

Click

**Plot**. This action creates an X-Y plane plot of the S_{12}parameters in the frequency range 1.9 to 2.2 GHz.

General Circuit Element, General Passive Network, Output Port, S-Parameters Passive Network, Y-Parameters Passive Network

`z2s`

(RF Toolbox)

`interp1`

( MATLAB)

Was this topic helpful?