skrf.network.s2s_active

skrf.network.s2s_active(s, a)[source]

Return active s-parameters 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]:

\[\mathrm{active}(s)_{m} = \sum_{i=1}^N\left( s_{mi} a_i \right) / a_m\]

where \(s\) are the scattering parameters and \(N\) the number of ports

Parameters:

s (complex array) – scattering parameters (nfreqs, nports, nports)
a (complex array of shape (n_ports)) – forward wave complex amplitude (pseudowave formulation [2])

Returns:

s_act – active S-parameters for the excitation a

Return type:

complex array of shape (n_freqs, n_ports)