Hexagonal multi-beam analog RF aperture array

A spatially discrete temporally continuous antenna array analog signal processing scheme that can produce highly selective hexagonal beams is proposed. A three dimensional (3-D) infinite impulse response (IIR) filter transfer function having hexagonal beam shaped passbands in the 3-D space-time frequency domain ω is introduced. A hexagonal beam passband in ω produces a hexagonal radio beam in the array pattern, and having closely packed multiple hexagonal beams, one can optimally sense a given sky area in a typical radar/microwave imaging application. The proposed array processing scheme employs analog RF circuits for achieving scaling, summing and time delay as building blocks for the signal processing operation. The 3-D IIR filter transfer function is derived by considering an example 10th-order 1-D Butterworth prototype polynomial.