In this article, an ultra-wideband circular cross slot artificial magnetic conductor (CCS-AMC) based low profile ultra-wideband (UWB) antenna is designed and implemented. Reflection phase bandwidth (±90°) of 63.47% (5.7 to 11.0) GHz is achieved using the proposed CCS-AMC. Integration of CCS-AMC with UWB antenna improves the radiation pattern and gain for entire UWB range. Impedance bandwidth of 129.41% (2.4 to 11.2) GHz is achieved for the final prototype. In order to verify the concept, a UWB antenna with a compact size of (0.31 × 0.31 × 0.1) λo, (λo is the wavelength corresponding to the lowest operating frequency at 3.1 GHz) is fabricated and experimentally validated with CCS-AMC. Average gain improvement of 3.5 dBi (3–10.5 GHz) and a peak gain of 8.5 dBi at 8 GHz are obtained. Miniaturized structure with high gain makes this prototype a better candidate, especially for outdoor UWB application. © 2020 Elsevier GmbH