Compensating for the influence of human hand with two switchable antennas

A human hand or head in close proximity to a mobile terminal antenna causes impedance mistuning between the antenna and radiofrequency electronics, and absorption in the human tissue, deteriorating overall performance. This study aimed to clarify whether a two-antenna solution can reduce this effect, compared to a single-antenna solution. The studied two-antenna solution included placing switchable antennas both at the top and the bottom of a mobile terminal. User hand-induced performance deterioration was measured with a near field antenna measurement system, using a commercial hand phantom to model four different hand grips. The research covered the 824-894-MHz and 1850-2170-MHz frequency bands. The results of this study confirmed that the presence of a human hand weakens the antenna performance, especially in the lower frequency band. The total efficiency was improved by 2-9-dB for the lower band and by 1-2-dB for the higher band when using two switchable antennas instead of a single antenna. This study provides new understanding on compensating absorption losses. Terminal designers can utilise the results of this study when optimising antenna solutions.