Pattern diversity for on body communications

Abstract

Summary form only given. Nowadays, diversity is widely applied for receiving at base stations for mobile cellular systems. However there is no experimental or simulated analysis have been conducted for diversity on on-body systems. This motivation has lead to the experimental of diversity measurement in the on body environment using two different types of diversity antennas. All the measurements were carried out at 2.45 GHz. Its necessity is suggested by the need for higher performance when large quantity of data has to be transferred with higher speed. The antennas used for the measurements were a monopole antenna and a disk-loaded monopole antenna integrated with PIN diode switches as a transmitter and receiver, respectively. The beams of a pattern diversity antenna were switched very quickly and controlled by PIC microcontroller. In this analysis, postures with different levels of mobility have been studied and roughly classified as sitting and standing positions. During the measurements, in both sitting and standing postures, free movements are allowed for each part of the body like leaning down, turning the trunk, walking, kneeling, and moving arms pretending to handle objects like in a real environment. Five potential channels have been investigated: belt-to-chest, belt-to-wrist, belt-to-ankle, belt-to-head and belt- to-back. Transmitter antenna was always be placed on the belt on the left side of the body while other positions are for receiver which in the opposite side. The diversity performance is generally measured as a diversity gain. This gain can be obtained by implementing one of the diversity combining methods, namely Switched Diversity Combining. The results show improvement in the signal reliability that proves the applicability of a diversity scheme to on-body communication systems.