Impacts of Real Hands on 5G Millimeter-Wave Cellphone Antennas: Measurements and Electromagnetic Models

Penetration of cellphones into markets requires their robust operation in time-varying radio environments, especially for millimeter-wave communications. Hands and fingers of a human cause significant changes in the physical environments of cellphones, which influence the communication qualities to a large extent. In this article, referential cellphone antenna arrays at 28 and 39 GHz are designed, and then simplified electromagnetic (EM) models of them for simulations are developed. Their radiation properties are evaluated through near-field scanning of the two prototypes in free space, first for de-embedding the feedline loss of cellphone antennas. The similarity of radiation patterns between simplified models and cellphone mock-ups ensures the reliability for comparing the simulated and measured results involving real hand effects. Next, hand-antenna interaction radiation measurements are set up so that we validate radiation performance simulations that use computational models of real hands that are generated by the approach in Vaha-Savo et al. (2022) and cellphones, by carrying out measurements of the same real hands and cellphone mock-ups and comparing measured with simulated results, which we show to agree well. This enables future research and development of mm-wave handset antennas relying on realistic simulations during the design phase.