The effects of antenna gains and polarization on multipath delayspread and path loss at 918 MHz on cross-campus radio links

摘要

Results of delay spread and path loss measurements across a largencollege campus are presented. Two line-of-sight links were used withnthree different types of antennas to determine best polarizations andnpointing angles. Measurements show multipath is most severe whennantennas of different polarizations are used on each end of the link.nMinimum delay spreads are encountered when antennas of the samenpolarization are used and pointed directly toward each other. As long asnpolarizations are matched on each side of the link, polarization doesnnot have significant impact on delay spread or path loss. However,ncircularly polarized helical antennas offer multipath reduction over anwide range of pointing angles. This suggests that on point-to-pointncross-campus links where a single antenna is desired to serve a broadncoverage area, circular polarization could be used in lieu of channelnequalization to improve bit error rates in high-speed datannetworks