Store output power and phase information for amplifiers or mixers
rational class to represent RF components using a
rational function object of the form:
There are two ways to construct an rational function object:
You can fit a rational function object to the component data using the
You can use the
rfmodel.rational constructor to specify
the pole-residue representation of the component directly.
h = rfmodel.rational returns a rational function
object whose properties are set to their default values.
sets properties using one or more name-value pairs. You can specify multiple
name-value pairs. Enclose each property name in a quote
A— Poles of rational function object
Poles of rational function object, specified as a complex vector in radians/second. The property length is shown in:
where, n must be equal to the length
of the vector you provide for
is the number of poles in the rational function object. By default, this
property is empty.
C— Residues of rational function object
Residues of the rational function object, specified as a complex vector in radians/second. The property length is shown in
n, must be equal to the length of
the vector you provide for
the number of residues in the rational function object. By default, this
property is empty.
D— Frequency response offset
Frequency response offset, specified as a scalar. The default value is
Delay— Frequency response time delay
Frequency response time delay, specified as a scalar. The default value is
Name— Object name
'Rational Function'(default) |
Object name, specified as a
1-by-N character array.
This is a read-only property.
|Frequency response of a rational function and rationalfit function object|
|Step-signal response of rational function object|
|Approximate data using stable rational function object|
|Return true if rationalfit output is passive at all frequencies|
|Enforce passivity of a rationalfit output|
|Plot passivity of N-by-N rationalfit function output|
|Time response for rational function object|
|Write Verilog-A description of rational function object|
|Generate SPICE file from rationalfit of S-parameters|
Fit a rational function to data from an
S = sparameters('defaultbandpass.s2p'); freq = S.Frequencies; data = rfparam(S,2,1); fit = rationalfit(freq,data)
fit = rfmodel.rational with properties: A: [10x1 double] C: [10x1 double] D: 0 Delay: 0 Name: 'Rational Function'
Construct a rational function object,
rat, with poles at -4 Mrad/s, -3 Grad/s,and -5 Grad/s and residues of 600 Mrad/s,2 Grad/s and 4 Grad/s.
Perform frequency-domain analysis from 1.0 MHz to 3.0 GHz.
f = [1e6:1.0e7:3e9];
Plot the resulting frequency response in decibels on the X-Y plane.
[resp,freq]=freqresp(rat,f); figure plot(freq/1e9,20*log10(abs(resp))); xlabel('Frequency (GHz)') ylabel('Magnitude (dB)')
Read a file named
passive.s2p and fit the 2-by-2 S-parameters. Generate a SPICE file of these S-parameters.
S = sparameters('passive.s2p'); fit = rationalfit(S); generateSPICE(fit,'passive.ckt')
The circuit is saved in your current folder.