A Multiresonant Element for Bandwidth Enhancement of Circularly Polarized Reflectarray Antennas

A new kind of reflectarray element with multiple resonances and circular polarization property is proposed. The element consists of the combination of a complete ring and a split-ring connected by a pair of stubs. The required reflected phase is realized by the rotation of elements. The element is then used for constructing a 14 × 14 single-layered wideband circularly polarized reflectarray antenna, which covers the satellite communication band from 9 to 15 GHz. The element spacing of the design is 0.34λ
₀
at 12 GHz in order to enhance the aperture efficiency. The reflectarray was fabricated and tested, and the measured results are in good agreement with the simulated results. The overlapped bandwidth of 1 dB gain and 3 dB axial ratio is 25.8%. The aperture efficiency is up to 52% at 13 GHz and greater than 40% over a bandwidth of 37.5%.