X/Ku Dual-Band Single-Layer Reflectarray Antenna

In this letter, X/Ku dual-band single-layer reflectarray antenna is presented. The proposed reflectarray antenna operates in two separated bands with separate feeds. The reflectarray element is composed of a split ring with two phase delay lines and a phoenix patch. The split ring and phoenix patch are designed for operation at X- and Ku-bands, respectively. The split ring is selected as the lower frequency element because of the large enough internal space. The phase shift of these two elements does not depend on variation of external size, which provides a feasible method for designing dual-band elements. The lower band phase shift is obtained by changing the rotation angle of the phase delay lines. The movement of the inner loop of phoenix patch provides the required phase shift for the higher band. The proposed element realizes 360° phase shift range in both bands. The reflectarray is fabricated and measured to validate the design. The measured gains are 22.9 dBi at 8.5 GHz with aperture efficiency of 40%, and 28.8 dBi at 16 GHz with aperture efficiency of 44.8%. Besides, the 1 dB gain bandwidths are 20.5% (7.9-9.7 GHz) at lower band and 13.3% (14.7-16.8 GHz) at higher band.