A Grip Study for Talk and Data Modes in Mobile Phones

The human hand influences the performance of small terminal antennas, and it is the main cause for absorption and detuning. Despite its importance in mobile-phone design and validation processes, it is still difficult to take it into account because of a lack of knowledge in the area. In this paper, a rigorous investigation methodology is described for the study of mobile-phone grip styles over a sample population of 100 subjects. Two main grip styles are identified in the talk mode, while most of the people use both hands in data mode. The index finger location is confirmed to be in the back region of the handset in most cases. The grip style has direct implications in the definition of a phantom hand. Regarding the talk mode, a procedure to estimate the palm-handset gap is proposed. The inclination of the handset with respect to the side of the user's head depends on the mobile-phone form factor and size. Moreover, we show that for the data mode, a worst-case scenario categorization approach is more suitable due to the time-varying nature of the fingers' position on the handset.