Abstract: By establishing the three-dimension rotated human head model proximate to practical operations‚the electromagnetic radiation dosage emitted from vertical and rotational handset antennas into a human body was simulated through the finite-differencetime-domain （FDTD） method．The effects of a human body on antenna’s radiation characteristics including the pattern and the radiation efficiency‚were also investigated．Moreover‚the difference between the vertical and the tilted operations was analyzed．Calculated results indicate that the radiation dosage radiated to a human body in tilted operation is less than that in vertical operation in certain degree‚without remarkable influence on the communication quality．

Key words: monopole antenna, three-dimension rotation, radiation dosage, radiation characteristic