A single-layer wideband reflectarray with sub-wavelength phase-shifting elements

A single-layer wideband reflectarray antenna employing sub-wavelength phase-shifting elements is presented. The element is composed of double concentric square meander line rings and its size is a fifth of a wavelength. By changing the length of the meander line, a phase variation range of about 360° is achieved with an almost constant slop across the 9 to 11 GHz. Using this element, a 48 × 48 - element reflectarray antenna is designed. A measured 1.5-dB gain bandwidth of 18 % is achieved.