Title page for ETD etd-03102003-114057


Type of Document Master's Thesis
Author Dillard, Cindy Lin
Author's Email Address cdillard@vt.edu
URN etd-03102003-114057
Title A Study of Rough Surface Scattering Phenomena in the LMDS Band (28 GHz)
Degree Master of Science
Department Electrical and Computer Engineering
Advisory Committee
Advisor Name Title
Bostian, Charles W. Committee Chair
Midkiff, Scott F. Committee Member
Sweeney, Dennis G. Committee Member
Keywords
  • 28 GHz
  • LMDS
  • Radio wave propagation
  • Scattering
  • Rough surface
Date of Defense 2003-02-27
Availability unrestricted
Abstract
A Study of Rough Surface Scattering Phenomena

in the LMDS Band (28 GHz)

Cindy Lin Dillard

(ABSTRACT)

In this study, the properties of the reflected paths and scattering phenomena were investigated in the LMDS band (28 GHz). We used the newly developed sampling swept time delay short pulse (SSTDSP) sounder to collect field data in certain locations on the Virginia Tech campus. The sounder collected the channel impulse response analog waveform, sampled, digitized and reconstructed it. The stored data were used to produce the power delay profile and other channel parameters. In particular, we collected scattered and reflected data regarding the channel response with different incident angle and distance set-ups from brick and limestone walls. We used the reflected pulse width and maximum excess delay derived from each power delay profile to analyze the rough surface scattering phenomena. We found that limestone and brick walls exhibited some diffuse scattering. The reflected pulse of a limestone wall had more maximum excess delay spread than did a brick wall at -15dB power threshold. The mean maximum excess delay for the reflected pulse of the limestone wall measurement set-ups was more than two times that of the brick wall. With equal transmitter and receiver distances to the wall, we found that as the incident angle increased, the maximum excess delay decreased but the perpendicular reflection coefficient increased. It is recommended that for future study, a second generation SSTDSP sounder will replicate the measurement with larger distance and angle set-ups as well as in non-line-of-sight areas.

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