Two-Step Method for Millimeter-Wave Antenna Performance Assessment in 5G Smartphones

Abstract

A critical challenge for 5G is transitioning to the mm-Wave spectrum. Despite providing unprecedented data rates, mm-Waves also suffer high path loss, atmospheric absorption, and higher fluctuating channel conditions, sparking numerous paradigm shifts in the smartphone industry. Extending mm-Wave communications to smartphones requires first a comprehensive study to identify the antenna design/smartphone implementation challenges that impact the quality of communications. This work proposes a two-step assessment metric, the mmWAESI, to evaluate mm-Wave antennas' potential and limitations regarding their impact on system performance. First, it analyzes the spatial distribution of the smartphone-integrated beam steering array's radiated power. Then, it evaluates the antenna's influence on the MIMO performance, using a discrete, time-variant geometrical MIMO channel simulator to recreate any mm-Wave propagation scenario. For enhanced accuracy, mmWAESI accounts simultaneously for several communication aspects: antenna type, realistic radiation patterns, mobile phone form factor constraints, phone orientation, and user influence. The method is illustrated for two different 4-element linear arrays at 39 GHz, based on patch or monopole elements, integrated into smartphones. Their performance is compared under similar conditions, revealing that, unless array switching is employed, the smartphone's form factor and user influence will mask any potential advantage of the unperturbed array characteristics.