Circularly polarised sequential array with enhanced gain and bandwidth for applications in C-band

This study presents a single-layer via-less antenna array operating in circular polarisation for wide-band operation in C-band. The antenna comprises 2 × 2 disc based elements arranged in a sequential rotation architecture. Each element is tuned to exhibit multiple resonances with good circular polarisation performance over a broadband of frequencies. A proper feeding network is then designed so that the resulting array is capable of a wide-band operation and enhanced gain, equalising the frequency response of the set of elements. Simulations are validated by fabricating and measuring a prototype realised on a commercial FR408 dielectric substrate. Notwithstanding a dimension of only 7 × 7 cm2, that is only 1.66 λ02 at centre frequency, measured performance of the proposed array can be summarised in a gain better than 7 dB over an operation bandwidth of 24.45%, which is an unmatched result, given the via-less single-layer technology and the specific available area.