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

TL;DR

This study develops and verifies electromagnetic models of human hands and cellphone antennas at 28 and 39 GHz, demonstrating their impact on antenna radiation patterns through measurements and simulations, crucial for reliable millimeter-wave communication.

Contribution

It introduces the first electromagnetic models of real hands and cellphone antennas validated by measurements, enhancing understanding of hand effects on millimeter-wave cellphone performance.

Findings

Models closely match measured spherical coverage.

Measurement repeatability is within 0.5 dB.

Models effectively predict hand-induced variations.

Abstract

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 paper, electromagnetic models of real hands and cellphone antennas are developed, and their efficacy is verified through measurements for the first time in the literature. Referential cellphone antenna arrays at $28$ and $39$~GHz are designed. Their radiation properties are evaluated through near-field scanning of the two prototypes, first in free space for calibration of the antenna measurement system and for building simplified models of the cellphone arrays. Next, radiation measurements are set up with real hands so that they are compared with electromagnetic simulations of the interaction between hands and simplified models of the arrays. The comparison showed a close agreement in terms of spherical coverage, indicating the efficacy of the hand and antenna array models along with the measurement approach. The repeatability of the measurements is $0.5$~dB difference in terms of cumulative distributions of the spherical coverage at the median level.