Wide‐band circularly polarised antenna array using sequential phase feed structure and reinforced square radiating patch element

Abstract

A $2 \times 2$2×2 circularly polarised (CP) antenna array with four square radiating patch elements has been introduced here. The array elements are sequentially rotated and have been fed by a simple single-layer feeding network with sequential phase structure. This feeding network generates successive phase difference at its four outputs. To have a wide CP bandwidth, the proposed method of feeding network has been combined with new simple tuning stubs which are embedded in radiating patch elements. The common reflection coefficient bandwidth ($S_{11} \lt - 10\, {\rm dB}$S11<;-10 dB) and axial ratio (AR) bandwidth (AR <;3 dB) is 1000 MHz which covers 1.5-2.5 GHz frequency band and according to the centre frequency of 1.8 GHz, the frequency bandwidth is ~55.5%. Furthermore, the peak gain of the proposed antenna array is ~7.5 dBi at the frequency range of 1.7-2.3 GHz.