Single layer reflectarray with modified cross loop element for wideband applications

A Ka-band reflectarray consists of modified cross loop is investigated in this paper. The reflectarray consists of 30 × 30 unit cells and covering an area of 15cm × 15 cm. The unit cell is composed of a solid cross inside and a cross loop outside. Varying the lengths of the cross can lead to nearly 550^o linear phase shift curve. Using this technique, a single layer reflectarray that has a wider bandwidth and much more fabrication tolerance compared with conventional single-layer reflectarrays, fabricated and measured. The reflectarray configuration parameters are chosen through aperture efficiency optimized calculation. And the simulated gain of 31.7 dB and aperture efficiency of 46.7% are predicted at the center 32 GHz, respectively. 1.5 dB gain bandwidth close to 17% were achieved, which is better than the reflectarray with patch cells. This new reflectarray antenna is especially useful for millimeter-wave broadband applications.