An antenna-in-package (AiP) device includes a substrate stack having a ceramic substrate attached to an organic substrate, where a dielectric constant of the ceramic substrate is higher than a dielectric constant of the organic substrate. An antenna is on a top side of the ceramic substrate. An integrated circuit (IC) die is flip chip attached to a bottom side of the ceramic substrate or to a top surface of the organic substrate. The IC die includes a radio circuit including at least a transmitter, and there is at least one interconnect for coupling the radio circuit to the antenna.