Exploring beamforming performance versus complexity in reconfigurable aperture antennas

Reconfigurable aperture (RECAP) antennas consist of a regular array of reconfigurable elements confined to an aperture, representing a generalization of the reconfigurable antenna concept. RECAPs have the potential of supporting operations like beamforming, null steering, interference suppression, adaptive matching, and frequency and bandwidth agility in a single aperture. Although very complex RECAP structures theoretically have performance that is only limited by the physical extent of the aperture, high complexity is impractical due to increased loss, biasing difficulties, and system cost. This work reviews the RECAP antenna concept and focuses on the role of performance bounds imposed by limited complexity in practical RECAP structures. This initial effort studies empirical bounds on beamforming performance observed from detailed simulation of two idealized RECAP structures: (i) a 5 × 5 parasitic dipole array, and (ii) a 8 × 8 planar configuration of reactively connected patches. Performance bounds for limited complexity are identified, indicating the number of elements per wavelength and the states per reconfigurable element that are needed to capture most of the available performance.