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 0.34λ0at 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%.