5G systems are just reaching the market and their technological demands need to be fulfilled. Requirements such as lower latency, higher spectrum/energy efficiency along with higher data-rates are among some of the most challenging. Considering the growing need of interacting with multiple RF Frontends, along with the tendency of the millimeter waves migration, due to the wider bandwidth available, this paper proposes a dual-band antenna, operating in the Ka-band. This dual-band monopole-based structure isolates each frequency through the feeding network, guaranteeing high efficiency for both 28/38 GHz. Besides, measured bandwidths around 15% for each frequency were achieved.