EVALUATION OF PERSONAL COMMUNICATIONS DUAL-ANTENNA HANDSET DIVERSITY PERFORMANCE

In personal wireless communications systems, multipath propagation has a significant effect on system design and performance. signal strengt h fading caused by destructive interference between multiple replicas of the signal of interest arriving at the receiver over different path s often is the limiting factor in system range/fidelity. Antenna diver sity is one technique that can be used to help overcome multipath fadi ng, This paper presents a description of experiments, data processing, and results used to evaluate the diversity performance of three candi date dual-antenna handset configurations: two side-mounted planar-inve rted F antennas (PIFA's), a back-mounted PIFA with a top-mounted helix , a top-mounted PIFA, and a ''flip'' monopole. In particular, the indo or industrial, scientific, and medical (ISM) band (902-928 MHz) propag ation channel was of interest. These experiments did not include opera tor proximity effects, and in these tests, the dual-antenna handset re mained stationary while the transmitter was moved along predetermined indoor paths. The issue of data normalization for extraction of fast f ading behavior from measured data will be addressed, with results show ing its effect on observed correlation presented. Also, measured indoo r fading distributions are presented and seen to fit the Rician and Ra yleigh models well, From the diversity results presented, it is seen t hat the three proposed dual-antenna handsets yield sufficient decorrel ation to warrant consideration for use in diversity systems.