A Miniaturized Broadband High-Impedance Surface With Flexible Circular Polarization Sense

This communication presents a miniaturized (
$0.084\lambda _{0} \times 0.044\lambda _{0}$
) dual-layered broadband polarization-dependent high-impedance surface (PDHIS). The unit-cell (UC) structure consists of periodic narrow horizontal patch arrays and vertical meander lines on the top and bottom layers of a thin substrate (
$0.012\lambda _{0}$
), respectively. Using this arrangement, the phase difference between the orthogonal polarization’s of the reflector is enhanced to 180° ± 30° over a wide range of frequencies. The UC of the proposed PDHIS is 88.7% smaller and the measured 3-dB axial-ratio bandwidth is 168.27% broader than a conventional anisotropic HIS. Also, the proposed PDHIS is polarization agile and the circular polarization sense can be easily controlled by changing the alignment of the reflector with respect to the incident plane wave. An equivalent circuit model of the dual-layered anisotropic HIS is presented and the proposed structure is validated using simulations and measurements.