Shared Aperture 4G LTE and 5G mm-Wave Antenna in Mobile Phones With Enhanced mm-Wave Radiation in the Display Direction

Radiation in the display direction of the 5G millimeter-wave (mm-wave) antenna in mobile phones is challenging due to the obstruction from the display. In this article, a shared aperture 4G LTE and 5G mm-wave antenna in mobile phones with enhanced mm-wave radiation in the display direction is studied. The 5G mm-wave array, consisting of four slot elements, is constructed in the clearance of a 4G LTE antenna. For the shared aperture design, the interdigital coupling (IDC) structure, which has a slight effect on the 4G LTE antenna, is used as the ground of the slot element. To enhance the mm-wave radiation in the display direction, two groups of floating patches are applied. For the 4G LTE antenna, the measured −6 dB impedance bandwidths are 280 MHz (700–980 MHz) and 1220 MHz (1700–2920 MHz). The measured efficiency is higher than 40%. For the 5G mm-wave array, the measured overlapped −10 dB impedance bandwidth is 2.7 GHz (25.1–27.8 GHz). The measured mutual coupling among each element is lower than −16 dB. Within the 25.5–27.5 GHz, in the display direction, the measured peak gain is 10.4 dBi, and the 3 dB beam steering range reaches 90° (45°– 135°) with a gain higher than 7.5 dBi.