In this study, a modified antipodal Vivaldi antenna (AVA) with low cross-polarisation is proposed for ultra-wideband communications. The bandwidth offered by conventional single petal AVA is enhanced by adding another petal. This dual petal antenna occupies a small volume of 60 × 60 × 0.8 mm3 and provides operating bandwidth from 2.4 GHz to frequencies > 14 GHz. The proposed antenna configuration provides low cross-polarisation level which is <-15 dB over the entire operational band. The designed antenna offers realised gain > 5 dB and an average group delay variation of 0.5 ns. The prototype antenna is fabricated and tested to validate the simulation results. © The Institution of Engineering and Technology.