Equivalently Folded Lens-based Beamforming Networks for Antenna Size Reduction and Efficiency Enhancement in Multi-Beam Radiation

This paper investigates the size reduction of two-dimensional (2-D) lens based beamforming network (BFN) by equivalently folding the lens structure on the same substrate which is sandwiched by a pair of parallel plates. This in-same-substrate folding is realized by building a conducting wall at the middle of lens to apply the image theory and conceptually resemble the configuration of the original BFN lens. This technique is examined by applying it to design single beam and multi-beam BFN for planar array excitation. Various configurations are examined to illustrate this folding technique with numerical results shown to validate the design. Its examples in the phased array antenna radiation are also shown.