Common-Aperture Design of Sub-6 GHz and Millimeter-Wave Antennas for 5G Metal-Rimmed Smartphone

This letter presents a common-aperture design scheme of sub-6GHz and millimeter-wave (mm-wave) antennas for 5G metal-rimmed smartphone. The sub-6GHz antenna can form a high-efficiency antenna covering WWAN/LTE multiple bands by referring to the previous scheme of dual-loop structure composed of metal frame and the ground plane of PCB motherboard. The millimeter-wave antenna consists of a connected slot antenna array (CSAA) etched on the top metal frame and a monopole antenna array (MAA) arranged on the top ground clearance region. Due to the end-fire characteristics of connected slot antenna array and the broad-fire characteristics of monopole antenna array, the proposed millimeter-wave antenna for smartphone has good radiation uniformity in three-dimensional space. In addition, a band stop matching circuit are introduced into sub-6GHz antenna and a high pass filter (HPF) are introduced into millimeter-wave antenna to solve the interference problem of millimeter-wave antenna to sub-6GHz antenna in common-aperture design.