skrf.media.media.Media.__init__

Media.__init__(frequency, propagation_constant, characteristic_impedance, z0=None)

The Media initializer.

This initializer has flexible argument types. The parameters propagation_constant, characterisitc_impedance and z0 can all be either static or dynamic. This is achieved by allowing those arguments to be either:

• functions which take no arguments or
• values (numbers or arrays)

In the case where the media’s propagation constant may change after initialization, because you adjusted a parameter of the media, then passing the propagation_constant as a function allows it to change when the media’s parameters do.

Parameters :

frequency : Frequency object

frequency band of this transmission line medium

propagation_constant : number, array-like, or a function

propagation constant for the medium.

characteristic_impedance : number,array-like, or a function

characteristic impedance of transmission line medium.

z0 : number, array-like, or a function

the port impedance for media , IF its different from the characterisitc impedance of the transmission line medium (None) [a number]. if z0= None then will set to characterisitc_impedance

See also

from_csv()

function to create a Media object from a csv file containing gamma/z0

Notes

propagation_constant must adhere to the following convention,

• positive real(gamma) = attenuation
• positive imag(gamma) = forward propagation

the z0 parameter is needed in some cases. For example, the RectangularWaveguide is an example where you may need this, because the characteristic impedance is frequency dependent, but the touchstone’s created by most VNA’s have z0=1