Potential of a small array at 10 GHz for switchable on/off-body wearable sensor node purposes

In future´s massive multiple-input multiple-output (MIMO) systems, the usage of antenna arrays has a centre stage solving the dilemma of a link range vs. a data rate. From wearable application perspective, proposed antennas in open literature have been mainly passive single element configurations which are optimised for either off-or on-body communication purposes. Arrays can bring fundamental improvements for the purposes of a wireless body area network (WBAN) by enabling possibility to realize an electronically switchable on/off-body communication antenna configuration. As recent trends in wearable market have shown that cellular communications are becoming products, the purpose of this article is to present the potential of a small and relative simple array configuration for switchable on/off-body communications. In this paper, free space channel path gain S21 is compared for the antennas at 2.4 GHz with respect to an array at 10 GHz with the equal aperture. Body tissue characteristics are compared, too. The functionality of the proposed array is shown in terms of beam steering capability, E-field distributions and various E-field (Ex, Ey, Ez, and Eabs) components along a body phantom model.