skrf.plotting.smith(smithR=1, chart_type='z', draw_labels=False, border=False, ax=None, ref_imm=1.0, draw_vswr=None)[source]

Plot the Smith chart of a given radius.

The Smith chart is used to assist in solving problems with transmission lines and matching circuits. It can be used to simultaneously display multiple parameters including impedances, admittances, reflection coefficients, scattering parameters, noise figure circles, etc. [1]

  • smithR (number, optional) – radius of smith chart. Default is 1.

  • chart_type (str, optional) –

    Contour type. Default is ‘z’. Possible values are:

    • ’z’ : lines of constant impedance

    • ’y’ : lines of constant admittance

    • ’zy’ : lines of constant impedance stronger than admittance

    • ’yz’ : lines of constant admittance stronger than impedance

  • draw_labels (Boolean, optional) – annotate real and imaginary parts of impedance on the chart (only if smithR=1). Default is False.

  • border (Boolean, optional.) – draw a rectangular border with axis ticks, around the perimeter of the figure. Not used if draw_labels = True. Default is False.

  • ax (matplotlib.pyplot.Axes or None, optional) – existing axes to draw smith chart on. Default is None (creates a new figure)

  • ref_imm (number, optional) – Reference immittance for center of Smith chart. Only changes labels, if printed. Default is 1.0.

  • draw_vswr (list of numbers, Boolean or None, optional) – draw VSWR circles. If True, default values are used. Default is None.