Highly Compact Integrated Sub-6 GHz and Millimeter-Wave Band Antenna Array for 5G Smartphone Communications

Abstract

In this paper, a dual-band integrated compact phased-antenna array is proposed for fifth generation smartphone communication. The proposed single-layered substrate-based antenna array has a dual band, wideband, high gain, and wide beam steering function. The dual bands were achieved by passive integration of meandered lines and a microstrip patch antenna using a dual-stub-based filter. Owing to the small size of the antenna array (56.65 mm × 4.95 mm × 0.508 mm), it was installed on both the top and side metal frames of a smartphone in a vertical position, allowing a wide beam coverage with a high gain. The proposed antenna provided the –6 dB bandwidths of 250 MHz and 3520 MHz at 3.5 and 28 GHz, and the –10 dB bandwidths of 110 MHz and 1890 MHz were observed at 3.5 and 28 GHz, respectively. The radiation performance with a smartphone model and a hand phantom were analyzed in detail. Furthermore, a safety study on the power density and specific absorption rate of the arrays with frequency-dependent hand and head models was conducted. Finally, we fabricated an antenna array prototype, and compared the measured results with the simulation results, which showed a good agreement.