Increasing SINR of microwave Applebaum adaptive arrays using analog 2D-IIR space-time network-resonant beam filters

Application of two-dimensional (2-D) network resonant analog beam filters towards increasing the spatial selectivity of microwave Applebaum adaptive arrays is explored. By employing a continuous-time 2-D planar-resonant beam filter as a pre-filtering stage to an existing Applebaum adaptive array, the zero-manifold only array transfer function is modified to include complex 2-D pole manifolds at guaranteed practical-BIBO stability. Increased spatial selectivity of the proposed architecture is observed via a reduction in the side lobe level on average. Furthermore, introduction of the 2-D network-resonant beam filter increases the usable temporal bandwidth of the original adaptive filter and therefore reduces the directional beam pointing errors present in the original Applebaum system due to operational frequency mismatches. Proposed system exhibits average signal to interference and noise ratio (SINR) improvement of 7.4 dB for beam directions from 0° to 90° where relative improvement increases towards the end fire direction of the antenna array.