Convert S-parameters of 2-port network to voltage or power-wave transfer function
tf = s2tf(s_params)
tf = s2tf(s_params,z0,zs,zl)
tf = s2tf(s_params,z0,zs,zl,option)
tf = s2tf(hs)
tf = s2tf(hs,zs,zl)
tf = s2tf(hs,zs,zl,option)
hs— 2–port s-parameters
2-port S-parameters, specified as an RF Toolbox™ S-parameter object.
s_params— Scattering parameters2x2xM array (default)
Scattering parameters, specified as a complex 2-by-2-by-M array.
z0— Reference impedance50 ohms (default)
Reference impedance of S-parameters, specified in ohms.
zs— Source impedance50 ohms (default)
Source impedance of S-parameters, specified in ohms.
zl— Load impedance50 ohms (default)
Load impedance of S-parameters, specified in ohms.
option— Transfer function type1 (default) | integer
Transfer function type, specified as an integer equal to
1 — The transfer function
is the gain from the incident voltage, Va,
to the output voltage for arbitrary source and load impedances:
The following figure shows how to compute Va from the source voltage Vs:
For the S-parameters and impedance values, the transfer function is:
The following equation shows how the preceding transfer function
is related to the transducer gain computed by the
Notice that if Zl and ZS are real, .
2 — The transfer function
is the gain from the source voltage to the output voltage for arbitrary
source and load impedances:
You can use this option to compute
the transfer function by setting
This setting means that Γs = –1 and Vin = Vs.
3 — The transfer function
is the power-wave gain from the incident power wave at the first port
to the transmitted power wave at the second port:
Calculate the voltage transfer function of an S-parameter array:
ckt = read(rfckt.passive,'passive.s2p'); sparams = ckt.NetworkData.Data; tf = s2tf(sparams)
The following figure shows the setup for computing the transfer function, along with the impedences, voltages, and the power waves used to determine the gain.
The function uses the following voltages and power waves for calculations:
Vl is the output voltage across the load impedance.
Vs is the source voltage.
Vin is the input voltage of the 2-port network.
is the incident power wave, equal to .
is the transmitted power wave, equal to .