Mutual-coupling based phased-array calibration: A robust and versatile approach

The transmit and receive modules of a large phased array are often calibrated for amplitude and phase variations by an internal calibration network and an offline characterization of the complete array in an anechoic chamber. Such a solution is less obvious in view of current trends towards integration and modularity. An alternative to surpass network and offline characterization is mutual-coupling based calibration. However, existing stepwise procedures for resolving the module transfer characteristics from (active) coupling measurements can be subject to propagating errors originating from e.g. measurement noise, manufacturing differences, and defective modules. In this paper we propose an alternative approach, which is more versatile and robust than a stepwise procedure, and we test this approach for two different array architectures with simulated coupling data.