Multiport amplifier input network with compensation for output network gain and phase frequency response imbalance

A satellite, comprising:

• a plurality of receive antennae;
• a plurality of transmit antennae;
• a multiport amplifier coupled between the plurality of receive antennae and the plurality of transmit antennae, the multiport amplifier including:
• an input hybrid matrix coupled to multiple ones of the receive antennae;
• an output hybrid matrix coupled to multiple ones of the transmit antennae;
• a plurality of amplification units coupled between the input hybrid matrix and the output hybrid matrix, the plurality of amplification units configured to amplify signals from the input hybrid matrix;
• and
• a plurality of equalizers, each coupled between the input hybrid network and the output hybrid matrix in series with a corresponding one of the amplification units, the equalizers configured to equalize signal paths between the receive antennae and the transmit antennae through the plurality of amplification units;
• and
• one or more calibration circuits connected to the multiport amplifier, the calibration circuits configured to generate and inject a calibration signal into a plurality of signal paths of the multiport amplifier before the equalizers concurrently with the multiport amplifier propagating one or more user signals along the signal paths, the calibration signal being a spread spectrum signal with a power level lower than a noise floor of the one or more user signals, the one or more calibration circuits further configured to receive the injected calibration signal after propagation through the multiport amplifier and perform a comparison of the injected calibration signal to the calibration signal after propagating through the multiport amplifier.