Single-Layer Polarization-Insensitive Dual-Band Reflectarray

This letter presents a single-layer polarization-insensitive shared-aperture reflectarray (RA) operating at dual-band. First, based on the spin-decoupled strategy, and by setting the identical phase patterns individually for left-handed and right-handed circularly polarized (LHCP and RHCP) waves, thereby the polarization-insensitive operation is deduced. Then, the RA element composed of the outer <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> element with a concentric split ring configuration and the inner <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i> element with a Malta cross configuration is designed to operate at <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> band, respectively. Subsequently, by considering the mutual influence between the RA elements operating at <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i> band, 2-bit phase coding for the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> element and 3-bit phase coding for the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i> element is proposed. Finally, the dual-band polarization-insensitive RA is designed, fabricated, and measured. The measured results are in good agreement with the simulated ones, realizing the similar focusing behavior under full-polarized incident waves at dual-band, and the polarization states of the generated beams are determined by the polarization states of the feed source.