Dual-Polarized mm-Wave Endfire Chain-Slot Antenna for Mobile Devices

This article describes a dual-polarized endfire antenna array for millimeter-wave (mm-wave) frequencies. The antenna consists of a chain-slot-shaped pattern on a mobile phone metal frame. The antenna is fed using a transmission line, which would cause only a negligible capacitive loading of the sub-6 GHz antenna realized on the same metal frame and, therefore, would not significantly degrade its performance. This makes colocating the sub-6 GHz and mm-wave antennas in the same, shared volume possible. Measurements indicate that a four-element array placed within a mobile phone provides a realized gain between 8 and 12.6 dBi for both polarizations across the entire band from 24.5 to 29.5 GHz. The total efficiency of a single element is better than -2 and -3 dB for the whole band for horizontal and vertical polarizations, respectively.