In this study, a wideband circularly polarised (CP) antenna is developed and demonstrated. The antenna comprises of two-layered substrates, the top layer holds a driven patch and eight surrounding parasitic patches of similar dimensions, and substrate integrated waveguide (SIW) based feeding topology is designed at the bottom layer. The driven patch is excited through coupling mechanism using a cross-slot carved on the upper clad of the SIW. The corners of the driven patch are curtailed and arms of the coupling slot made unequal, which constructively generates the CP wave. Moreover, the proposed antenna is prototyped, and experimentally verified. The antenna shows measured impedance and axial-ratio (AR) bandwidths of 1.29 GHz (21 per cent) and 460 MHz (7.35 per cent), respectively, while maintaining the high gain of ~8 dBic over the operating CP region. This design aids the favorable characteristics such as light weight, wide impedance and (AR) bandwidths, high-gain as well as lenience of production, and integration. © 2019, DESIDOC.