In a PDA position, geometrical relationships between the terminal and the human body are considerably different from those of the ordinary talk position. This can give different EM interactions due to antenna-human body couplings, resulting in inherent diversity effects. In order to verify this phenomenon, a high-precision human phantom with a very realistic shape that represents a man holding a terminal in a PDA position has been developed. The dimensions were determined from the average of 34,000 Japanese people in a statistical database. Furthermore, additional measurements were done by sampling 38 parts of the human body for forty-four 20 to 30-year-old men holding a mobile terminal in a PDA situation. From the 3D-radiation measurements of a handset diversity antenna close to a human phantom, the antenna gain in front of the body was founded to periodically change as a function of the handset-human body distance D. On the other hand, the mean effective gain remained almost constant as D changed.
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