skrf.media.Media

class skrf.media.Media(frequency=None, z0_port=None, z0_override=None, z0=None)[source]

Abstract Base Class for a single mode on a transmission line media.

This class init’s with frequency and z0_port (the port impedance); attributes shared by all media. Methods defined here make use of the properties :

  • gamma - (complex) media propagation constant

  • z0 - (complex) media characteristic impedance

Which define the properties of a specific media. Any sub-class of Media must implement these properties. gamma and z0 should return complex arrays of the same length as frequency. gamma must follow the convention:

  • positive real(gamma) = attenuation

  • positive imag(gamma) = forward propagation

Parameters:
  • frequency (Frequency object or None) – frequency band of this transmission line medium. Defaults to None, which produces a 1-10ghz band with 101 points.

  • z0_port (number, array-like, or None) – z0_port is the port impedance for networks generated by the media. If z0_port is not None, the networks generated by the media are renormalized (or in other words embedded) from the characteristic impedance z0 of the media to z0_port. Else if z0_port is None, the networks port impedances will be the raw characteristic impedance z0 of the media. (Default is None)

  • z0_override (number, array-like, or None) – z0_override override the characteristic impedance for the media. If z0_override is not None, the networks generated by the media have their characteristic impedance z0 overrided by z0_override. (Default is None)

  • z0 (number, array-like, or None) – deprecated parameter, alias to z0_override if z0_override is None. Emmit a deprecation warning.

Notes

Full-wave simulations results can be networks with complex and frequency-dependant z0 port impedances. However, the regular touchstone (s-parameters) files generated by most VNA measurements are normalized to a single real value, e. g. 1. or 50 ohm. Manually setting the z0_port to a single real value enforce the second behaviour. The default (z0_port = None) is the first behaviour.

Attributes

Z0

Characteristic Impedance

alpha

Real (attenuation) component of gamma.

beta

Imaginary (propagating) component of gamma.

gamma

Propagation constant.

npoints

Number of points of the frequency axis.

v_g

Complex group velocity (in m/s).

v_p

Complex phase velocity (in m/s).

z0

Return Characteristic Impedance z0_characteristic.

z0_characteristic

Characteristic Impedance, \(z_0\).

z0_override

Port Impedance.

z0_port

Port Impedance.

Methods

__init__

attenuator

Ideal matched attenuator of a given length.

capacitor

Capacitor.

capacitor_q

Capacitor with Q factor.

copy

Copy of this Media object.

delay_load

Delayed load.

delay_open

Delayed open transmission line.

delay_short

Delayed Short.

electrical_length

Calculate the complex electrical length for a given distance.

extract_distance

Determines physical distance from a transmission or reflection Network.

get_array_of

impedance_mismatch

Two-port network for an impedance mismatch.

inductor

Inductor.

inductor_q

Inductor with Q factor.

isolator

Two-port isolator.

line

Transmission line of a given length and impedance.

load

Load of given reflection coefficient.

lossless_mismatch

Lossless, symmetric mismatch defined by its return loss.

match

Perfect matched load (\(\Gamma_0 = 0\)).

mode

Create another mode in this medium.

open

Open (\(\Gamma_0 = 1\)).

plot

random

Complex random network.

resistor

Resistor.

short

Short (\(\Gamma_0 = -1\))

shunt

Shunts a Network.

shunt_capacitor

Shunted capacitor.

shunt_delay_load

Shunted delayed load.

shunt_delay_open

Shunted delayed open.

shunt_delay_short

Shunted delayed short.

shunt_inductor

Shunted inductor.

shunt_resistor

Shunted resistor.

splitter

Ideal, lossless n-way splitter.

tee

Ideal, lossless tee.

theta_2_d

Convert electrical length to physical distance.

thru

Matched transmission line of length 0.

to_meters

Translate various units of distance into meters.

white_gaussian_polar

Complex zero-mean gaussian white-noise network.

write_csv

write this media's frequency, gamma, Z0, and z0 to a csv file.