skrf.network.Network

class skrf.network.Network(touchstone_file=None, name=None)

A n-port electrical network.

A n-port network may be defined by three quantities,

• scattering parameter matrix (s-matrix)
• port characteristic impedance matrix
• frequency information

The Network class stores these data structures internally in the form of complex numpy.ndarray’s. These arrays are not interfaced directly but instead through the use of the properties:

Property	Meaning
s	scattering parameter matrix
z0	characteristic impedance matrix
f	frequency vector

Individual components of the s-matrix are accesable through properties as well. These also return numpy.ndarray’s.

Property	Meaning
s_re	real part of the s-matrix
s_im	imaginary part of the s-matrix
s_mag	magnitude of the s-matrix
s_db	magnitude in log scale of the s-matrix
s_deg	phase of the s-matrix in degrees

The following Network operators are available:

Operator	Function
+	element-wise addition of the s-matrix
-	element-wise difference of the s-matrix
*	element-wise multiplication of the s-matrix
/	element-wise division of the s-matrix
**	cascading (only for 2-ports)
//	de-embedding (for 2-ports, see inv)

Different components of the Network can be visualized through various plotting methods. These methods can be used to plot individual elements of the s-matrix or all at once. For more info about plotting see the Plotting tutorial.

Method	Meaning
plot_s_smith()	plot complex s-parameters on smith chart
plot_s_re()	plot real part of s-parameters vs frequency
plot_s_im()	plot imaginary part of s-parameters vs frequency
plot_s_mag()	plot magnitude of s-parameters vs frequency
plot_s_db()	plot magnitude (in dB) of s-parameters vs frequency
plot_s_deg()	plot phase of s-parameters (in degrees) vs frequency

Generally, Network objects are created from touchstone files upon initializtion (see __init__()), or are created from a Media object. Network objects can be saved to disk in the form of touchstone files with the write_touchstone() method.

An exhaustive list of Network Methods and Properties (Attributes) are given below

Attributes

f	the frequency vector for the network, in Hz.
frequency	frequency information for the network.
inv	a Network object with ‘inverse’ s-parameters.
nports	the number of ports the network has.
number_of_ports	the number of ports the network has.
passivity	passivity metric for a multi-port network.
s	the scattering parameter matrix [#]_.
t	t-parameters, aka scattering transfer parameters [#]_
y	admittance parameters
z	impedance parameters
z0	the characteristic impedance[s] of the network ports.

Methods

__init__	constructor.
add_noise_polar	adds a complex zero-mean gaussian white-noise.
add_noise_polar_flatband	adds a flatband complex zero-mean gaussian white-noise signal of
copy	returns a copy of this Network
flip	swaps the ports of a two port Network
interpolate	calculates an interpolated network.
interpolate_self	interpolates s-parameters given a new
interpolate_self_npoints	interpolate network based on a new number of frequency points
multiply_noise	multiplys a complex bivariate gaussian white-noise signal
nudge	perturb s-parameters by small amount. this is useful to
plot_it_all
plot_passivity	plots the passivity of a network, possibly for a specific port.
plot_s_smith	plots the scattering parameter on a smith chart
read_touchstone	loads values from a touchstone file.
renumber	renumbers some ports of a two port Network
write_touchstone	write a contents of the Network to a touchstone file.