Fifth generation mobile networks will introduce several new frequencies for short-range high-capacity communications. Future handsets must also support current frequency bands for backwards compatibility and long-range communications. This paper presents a proof-of-concept solution for co-designed millimeter-wave and LTE antennas in a metal-rimmed handset. The design shows that both antenna types can be accommodated within the volume and be integrated into the same structure. Presented antennas operate at 700–960 MHz, 1710–2690 MHz, and 25–30 GHz. Simulations and measurements suggest the system can be designed in such a way that the millimeter-wave antenna does not hinder the low band performance. LTE antennas generally reach over 60% total efficiency while the millimeterwave module has a peak gain of 7 dBi with measurementverified beam-steering capability. The proposed design proves that 5G mm-wave antennas can be embedded to 4G systems without greatly sacrificing display size or sub-6 GHz antenna performance.