Single-layer wideband circularly polarized antenna array using sequential phase feed for C-band applications

This paper proposes a circularly polarized 2 × 2 antenna array for C-band wireless applications. The most attractive feature of the proposed design is that it is only fabricated on a single layer of a dielectric substrate, while maintaining wideband operation and high gain radiation as well. The single-layer design is able to significant reduce the antenna’s complexity. The array element is based on a truncated corner patch and a periodic structure. The final prototype of 2 × 2 antenna array with overall dimensions of 1.2λ × 1.2λ × 0.04λ, where λ is the lowest operating frequency, was fabricated and experimentally validated. The proposed array yields a measured impedance bandwidth of 42.9% (4.4–6.8 GHz) and a measured 3-dB axial ratio bandwidth of 36.4% (4.5–6.5 GHz). Within the operating band, good radiation patterns are achieved and the boresight gain is from 9.5 to 11.5 dBic. Compared with the other reported single-layer sequential-fed antenna arrays in literature, the proposed shows the best operating bandwidth with competitive gain radiation.