A slot antenna assembly for a portable electronic device is disclosed. The assembly includes a first slot antenna having a first slot through a substrate from an outer surface of the substrate to an inner surface of the substrate. The assembly also includes a second slot antenna including a second slot through the substrate from the outer surface of the substrate to the inner surface of the substrate. An isolator includes at least one of an isolation slot and a conductor. The isolation slot includes a substrate isolation slot which extends through the substrate between the first and second slot antennas; and a conductor. The conductor connects the inner surface of the substrate between the first and second antennas to an opposite inner surface of an opposite substrate opposite the inner surface between the first and second antennas.