Slot Antenna Performance and Signal Quality in a Smartphone Prototype

Antenna position and user grip on smartphone-like devices may lead to obstruction of radio signal paths and antenna detuning. A multiple-input-multiple-output (MIMO) outdoor propagation measurement campaign is presented, which collected data for slot antennas on a smartphone prototype. The antennas are in four positions, two polarizations, and one was obstructed due to operator grip. All MIMO links were measured within the channel´s coherence time while standing, walking, and driving. We show how signal levels change due to obstruction, position, and motion and that signal fluctuations increase significantly, thus tending to impair service quality. We also examine how proximity of the operator´s hand affects the antenna´s radiation and input characteristics.