skrf.circuit.Circuit.s_active

Circuit.s_active(a)[source]

Return “active” s-parameters of the circuit’s network for a defined wave excitation a.

The “active” s-parameter at a port is the reflection coefficients when other ports are excited. It is an important quantity for active phased array antennas.

Active s-parameters are defined by [1]:

\[\mathrm{active}(s)_{mn} = \sum_i s_{mi} \frac{a_i}{a_n}\]

Parameters:: a (complex array of shape (n_ports)) – forward wave complex amplitude (power-wave formulation [2])
Returns:: s_act – active s-parameters for the excitation a
Return type:: complex array of shape (n_freqs, n_ports)

References