RF Blockset™

Y-Parameters Passive Network - Model passive network using Y-parameters

Library

Black Box Elements sublibrary of the Physical library

Description

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

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

The Y-Parameters Passive Network block uses the RF Toolbox™ y2s function to convert the Y-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™ Algorithms for more details.

Dialog Box

Main Tab

Y-Parameters

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

Frequency (Hz)

Frequencies of the Y-parameters as an M-element vector. The order of the frequencies must correspond to the order of the Y-parameters in Y-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

Visualization Tab

For information about plotting circuit parameters, see Plotting Model Data.

Examples

Plotting Parameters with the Y-Parameters Passive Network Block

The following example specifies Y-parameters [.23i, -.12i; -.12i, .23i] and [.02-.13i, -.02+.25i; -.02+.25i, .02-.13i] at frequencies 2.0 GHz and 2.1 GHz respectively. It uses the MATLAB^® cat function to create the 2-by-2-by-2 Y-parameters array.

cat(3,[.23i,-.12i;-.12i,.23i],...
      [.02-.13i,-.02+.25i;-.02+.25i, .02-.13i])

Type the following command at the MATLAB prompt to create a variable called yparams that stores the values of the Y-parameters.
```
yparams = cat(3,[.23i,-.12i;-.12i,.23i],...
      [.02-.13i,-.02+.25i;-.02+.25i, .02-.13i])
```
Set the Y-Parameters Passive Network block parameters on the Main tab as follows:
- Set the Y-Parameters parameter to yparams.
- Set the Frequency (Hz) parameter to [2.0e9,2.1e9].
Click Apply. This action applies the specified settings.
Set the Y-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 Plot type list, select Polar plane.
Click Plot. This action creates a polar plane plot of the S₁₁ parameters in the frequency range 1.9 to 2.2 GHz.