A High-Efficiency Ku-Band Reflectarray Antenna Using Single-Layer Multiresonance Elements

A broadband single-layer reflectarray antenna composed of multiresonance square-rings elements is presented. The element is optimized to provide a linear phase curve and wide-enough phase variation. To avoid feed blockage, an offset feed configuration is used, and wave incident angle is considered to determine the appropriate element parameters that provide desirable phase shift on the antenna surface. The aperture efficiency of the antenna is maximized by optimizing feed position and characteristics. A 480-element antenna is fabricated and measured. The measured results show 1-dB gain bandwidth of 17% and radiation efficiency of 66% at 13.5 GHz center frequency.