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# s2t

Convert S-parameters to T-parameters

## Syntax

t_params = s2t(s_params)

## Description

t_params = s2t(s_params) converts the scattering parameters s_params into the chain scattering parameters t_params. The s_params input is a complex 2-by-2-by-M array, representing M 2-port S-parameters. t_params is a complex 2-by-2-by-M array, representing M 2-port T-parameters.

This function uses the following definition for T-parameters:

$\left[\begin{array}{c}{a}_{1}\\ {b}_{1}\end{array}\right]=\left[\begin{array}{cc}{T}_{11}& {T}_{12}\\ {T}_{21}& {T}_{22}\end{array}\right]\left[\begin{array}{c}{b}_{2}\\ {a}_{2}\end{array}\right],$

where:

• a1 is the incident wave at the first port.

• b1 is the reflected wave at the first port.

• a2 is the incident wave at the second port.

• b2 is the reflected wave at the second port.

## Examples

Convert S-parameters to T-parameters:

```%Define a matrix of S-parameters
s11 = 0.61*exp(j*165/180*pi);
s21 = 3.72*exp(j*59/180*pi);
s12 = 0.05*exp(j*42/180*pi);
s22 = 0.45*exp(j*(-48/180)*pi);
s_params = [s11 s12; s21 s22];
%Convert to T-parameters
t_params = s2t(s_params)```

## References

Gonzalez, Guillermo, Microwave Transistor Amplifiers: Analysis and Design, 2nd edition. Prentice-Hall, 1997, p. 25.