Effect of Human Body on 3-D Radiation Pattern and Efficiency of Mobile Handsets

Mobile handsets are used in proximity to user´s body and this reduces the transmitted or received power of the handset. In this paper it is investigated how the human body affects the radiation characteristics, e.g. radiation pattern and total efficiency. The test handset is an active GSM mobile phone and the experiments are 3-D far-field radiation pattern measurements in an anechoic chamber at the 1800 MHz band. In particular it is studied how large differences occur in the results between different test persons when they hold the mobile phone as similarly as possible. Moreover, in the second experiment the measurements are performed so that the mobile phone is against the test user´s head but the user does not hold the phone in his/her hand. The variation in the total radiated power (or efficiency) between the three test persons was only about 0.2 dB. The average body loss due to the user´s head was 1.6 dB. The additional body loss due to the user´s hand was 2.6 dB. The results for a phantom agreed well with the results for the test persons, when only the head was included in the measurements