In this paper, a hybrid antenna array for 4G/5G smartphone applications is presented. The hybrid antenna system is composed of one array of two antenna elements for 4G application and another array of six antenna elements for 5G application. By loading PIN diodes and changing the on/off state of the PIN switch, then the resonance point will shift. The 2-antenna array broadens the bandwidth of 4G frequency band and is capable of covering GSM850/900/DCS1800/PCS1900/UMTS2100 and LTE2300/2500 operating bands. A U-shape monopole strip and an S-shape slot coupling technologies are also introduced, the 6-antenna array improves the impedance matching for the proposed 5G antenna array and is capable of covering the 5G (3300-3600 MHz and 4800-5000 MHz), which can meet the demand of 5G application. Spatial and polarization diversity techniques are implemented on these antenna elements so that high isolation can be achieved. This hybrid antenna array is fabricated, and typically experimental results such as S 11 , isolation, radiation pattern efficiency, and channel capacity are presented. The measured results are in good agreement with the simulated ones.