The effects of antenna directivity on path loss and multipath propagation in UWB indoor wireless channels

The effects of antenna directivity on path loss and multipath propagation in the ultra-wideband (UWB) indoor channel are analyzed for different transmitter/receiver (Tx/Rx) antenna combinations in the 2 GHz to 6 GHz frequency band. A statistical model of the path loss in the channel is presented, where the parameters in the model (i.e., path loss exponent and shadow fading statistics) are dependent on the particular Tx/Rx antenna combination. Time domain statistics of the channel (i.e., mean delay spread and RMS delay spread) are analyzed thoroughly for each antenna combination. There is a significant reduction in RMS delay spread when directional antennas are used at the transmitter and receiver as opposed to using omni-directional antennas. Results show that directional antennas can be used as an effective way of mitigating the effects of multipath propagation in UWB indoor channels.