Difference of Path-Loss Characteristics due to Mobile Antenna Heights in Microwave Urban Propagation

Hironari MASUI  Koichi TAKAHASHI  Satoshi TAKAHASHI  Kouzou KAGE  Takehiko KOBAYASHI  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E82-A   No.7   pp.1144-1150
Publication Date: 1999/07/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Multi-dimensional Mobile Information Networks)
microwave propagation,  urban areas,  path loss,  break point,  mobile antenna height,  

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This paper discusses microwave path-loss characteristics as a function of mobile antenna height in an urban line-of-sight environment. Measurements were made in metropolitan Tokyo with high-density buildings, using base station antenna heights of 4 and 8 m. We describe the path-loss characteristics of vehicle-mounted mode (mobile antenna height is 2.7 m) and portable mode (mobile antenna heights are 1.6 and 0.5 m). Dependence of path loss on the distance between base and mobile stations was analyzed. This reveals that the break points shift to the near side in the vehicle-mounted mode. This phenomenon can be interpreted by the existence of an effective height h of the road. The typical value of h was found approximately 1.4 m. In the portable mode, on the other hand, break points were not observed. The mobile antenna heights (1.6 and 0.5 m) in this mode are close to or less than the average height (1-2 m) of pedestrians on the sidewalk; and the received waves at the mobile station are often disturbed by pedestrians. This explains the nonexistence of break points in portable mode. The average attenuation coefficients is observed 3.2 in this mode. The attenuation coefficients tend to be larger at lower base station antenna heights and narrower road widths.