Metasurface Dome Enhancing Beam Scanning of Active Electronic Arrays

Active Electronically Scanned Arrays (AESA) provide a limited beam scanning range without experiencing impedance mismatch or producing secondary lobes. This field of view (FoV) limitation becomes critical for the implementation of localization systems. This study evaluates the improvement in the scanning performance achievable by combining an AESA panel with a properly designed dome-shaped metasurface. To this end, we present a general technique to achieve wide-angle matching for the AESA panel system by jointly designing the dome’s phase profile and the array’s complex excitation. The approach for the design of the metasurface implementing the desired phase profile is also discussed. When such a structure is perfectly matched, it can be referred to as Huygens’ metasurface, which is typically made of electrically small elements forming a triplet of cascaded admittances. By properly shaping them, it is possible to achieve perfect matching and complete phase control, which is used to introduce the phase gradient needed deflect the rays in the desired direction. The introduction of the dome would imply a certain gain loss when the array is fed with a linear phase. The AESA panel’s configurability is exploited to compensate for this effect, thus, making the dome’s phase function work throughout the whole angular range. This is illustrated in Fig.1, showing how the array is fed with a non-linear phase to obtain perfect collimation beyond the dome. Furthermore, this excitation has a beneficial effect on the active scattering coefficients. © 2024 IEEE.