Single-Layered Broadband Dual-Band Reflectarray With Linear Orthogonal Polarizations

Abstract

This communication presents a single-layered broadband dual-band reflectarray with linear orthogonal polarizations in two adjacent bands. The reflectarray is designed to focus a broadside beam at 10.7–12.7 GHz band in vertical polarization and 12.7–14.7 GHz band in horizontal polarization, respectively. Different from the traditional square grids adopted in many reflectarray designs, this communication proposes subwavelength rectangular grids in a single-layered structure for achieving broad bandwidth in both the bands. Two pyramidal horn antennas with opposite positions are employed to feed the reflectarray for vertical and horizontal polarizations, respectively. The elements consist of single-layered patches arranged in subwavelength rectangular grids. To realize the dual-band operation, one dimension of the patches is adjusted to direct the beam at the lower band in vertical polarization, whereas the other orthogonal dimension is tuned to focus the beam at the upper band in horizontal polarization. The measured results show that the proposed dual-band reflectarray can realize a broad 1.5-dB gain bandwidth of 24% and 21% with aperture efficiency of 48% and 38% for the lower and upper band, respectively, which demonstrates better behavior than various existing dual-band designs adopting traditional square grids.