A wideband low‐profile dual‐circularly polarized reflectarray with decoupled LHCP/RHCP beams

Abstract

AbstractThis letter presents the design principle and experimental verification of a Ku‐band wideband low‐profile dual‐circularly polarized (dual‐CP) reflectarray (RA) with independent control of left‐/right‐handed circularly polarized (LHCP/RHCP) beams. Both the dynamic phase (DP) and Berry phase (BP) compensating methods are employed in the design of the unit cell, achieving independent LHCP/RHCP phase modulation based on the single‐functional‐layer concept. A single‐layer unit cell is designed, offering a ‐bit dual‐CP phase shift which facilitates the independent control of LHCP/RHCP beams. A prototype with asymmetrical dual‐CP beams is fabricated and tested. For LHCP and RHCP excitation, beam directions of () and () are realized, respectively, with sidelobe levels and cross‐polarizations both under −15 dB. The prototype exhibits a wide axial ratio (AR) bandwidth of over 36% with AR  dB. The overlapped 1‐dB gain and AR  dB bandwidth is 19.5% under LHCP input and 12.2% under RHCP input, with maximum aperture efficiency of 41.3% and 34.6%, respectively. The proposed dual‐CP RA exhibits broad band, pure chirality, high gain, low profile and independent polarization control, with single‐layer construction which is of low cost and easy processing.