Advanced diagnostics on array antennas from reconstructed equivalent current distribution

The inverse source or equivalent current/source method (EQC), [1]-[7], based on discretization of integral equations has attracted considerable attention due to a host of promising applications in antenna design and diagnostics. This method offers a greater generality and flexibility since it allows reconstructing sources on arbitrary 3-D surfaces enclosing the antenna under test (AUT). Indeed the equivalent source approach is a true 3D approach as opposed to traditional methods based on plane wave expansion using hemispherical field information. This method is therefore highly suitable for diagnostics on low and medium directivity antenna and even allows the possibility to identify and isolate unwanted effects close to the antenna. In this paper the measurement diagnostics capabilities of the tool are used for detecting possible electrical and/or mechanical defects on the antennas with particular attention to array antennas measured in different measurement scan ranges.