A Broadband Single-Layer Reflectarray Antenna Using Multiresonance Elements

A linearly polarized X-band reflectarray (RA), based on single layer multiresonance elements, is proposed in this paper. To enhance the bandwidth, the unit cell is composed of double gapped square loops and a gapped circular annular ring. The pair of gaps are spatially orthogonal to one another, and two extra phase delay lines are attached to the outer ring. The unit cell exhibits a 600° linear phase tuning range by adjusting the length of the delay lines. A 277-element RA using a 15° offset fed horn was fabricated and measured. The measured results show a 1-dB gain bandwidth of 14.2%, and a 3-dB gain bandwidth of 26.4%. The antenna gain at 10 GHz is 25.2 dBi, which is equivalent to an aperture efficiency of 50.9%.